Freshwater Fishes

Arctic char, is a cold water fish in the family Salmonidae. It is native to Arctic, sub-Arctic and alpine lakes. It breeds in fresh water. Char may either be landlocked or anadromous, migrating to the sea. No other freshwater fish is found as far north. It is the only fish species in Lake Hazenon Ellesmere Island in the Canadian Arctic. It is one of the rarest fish species in Britain. Found only in deep, cold, glacial lakes, and is at risk from acidification. In other parts of its range, such as Scandinavia, it is much more common, and is fished extensively. It is also common in the Alps, (particularly in Trentino and in the mountain part of Lombardy). Char are also found in Iceland. In Siberia, it is known as golets. The Arctic char is a relative of both salmon and lake trout. It shares traits with both. The char's color depends on the time of year and where it lives. The back is usually dark brown or olive green. It has dark spots on a light background on its sides, and the color can be gold, brown, red, or orange. At spawning, the fins and belly become bright red or orange.

The Arctic sculpin (Myoxocephalus scorpioides) or the northern sculpin, is a predatory species of sculpin in the fish family Cottidae.The species is native to the Arctic Ocean around Canada and Greenland, specifically in James Bay and the Strait of Belle Isle, and towards the Bering Sea. It has the ability to synthesize antifreeze proteins, allowing it to withstand temperatures as low as -2 °C. It serves as the host for Haemobaphes cyclopterina, a parasitic species of copepod.

The bigmouth buffalo (Ictiobus cyprinellus) is a fish native to North America, and it is in decline. It is the largest North American species in the Catostomidae or 'sucker' family, and is one of the longest-lived and latest-maturing freshwater fishes, capable of living beyond 110 years and reproducing infrequently.It is commonly called the gourdhead, marblehead, redmouth buffalo, buffalofish, bernard buffalo, roundhead, or brown buffalo. The bigmouth buffalo is not a carp, nor is any other fish in the sucker family. Although they share the same order, each belong to different suborders and are native to separate continents. The bigmouth buffalo is typically a brownish olive color with dusky fins, but can vary greatly in color across individuals. Like other catostomids it has a long dorsal fin, but unlike all others it has a terminal (forward-facing) mouth reflecting its unique, pelagic feeding ecology. It is the largest of the buffalo fish and can reach a length of more than 4 ft (1.2 m) and 65 lb (29 kg) in weight. Generally, it lives in sluggish areas of large rivers and in lakes. Bigmouth buffalo populations have been in decline in the northern extent of their range since the 1970s, including parts of Minnesota, North Dakota, and Canada.A 2019 study documented their late maturity, centenarian longevity, and that several populations in northwestern Minnesota are comprised mainly (85-90%) of individuals more than 80 years old, indicating recruitment failure since the 1930s. These life history attributes, including the ability to survive decades with virtually no successful recruitment (i.e. periodic recruitment), are shared by other long-lived freshwater fishes, including sturgeon.Such species require time to successfully sustain themselves, surviving to periods in which favorable environmental conditions arise that allow for booms in reproduction and subsequent recruitment.Management of bigmouth buffalo is thus in urgent need of reevaluation, at least in the northern part of their US range where populations are already declining;there are no limits on harvest, and night bowfishing was recently legalized, allowing a new and growing form of exploitation. The bigmouth buffalo has a rather unique, pelagic ecology of shallow-water systems. The larval bigmouths are pelagic and sometimes benthic feeders of copepods and cladocerans mostly, but also eat phytoplankton and chironothemids. Bigmouth buffalo, unlike its close relatives the black and smallmouth buffalos, is a pelagic filter-feeder, using its very fine gill rakers to strain zooplankton from the water. It sometimes feeds near the bottom, using short up-and down movements to filter from the water the animals that hover near the bottom or rest lightly on it. The juveniles and adults are mostly limnetic plankton feeders that also eat cladocera, copepods, algae, Chironomidae, ostracods, and other insect larvae and invertebrates depending on availability. The optimum habitat for spawning bigmouth buffalo is highly vegetated waters. They are a very resilient fish that can tolerate high turbidity and low oxygen levels. They can be found in waters with turbidity levels over 100 ppm. A minimum total dissolved solids is 200 ppm during the growing season. During spring and summer, 50–75% pools should be present, with backwaters, and marsh areas and 25-75% littoral area and protected embayments during summer for the habitat to be suitable. Bigmouth can be found in waters from 22.5–38.0 °C, but their preferred temperature is between 31 and 34 °C. The optimal temperatures for incubation and hatching of eggs are from 15-18 °C, but they can develop in temperatures reaching up to 26.7 °C. The bigmouth prefers slow-moving water that does not reach a velocity over 30 cm/s. Salinity can be a problem for reproduction. Spawning can occur from 1.4-2.0 ppt of salinity which eggs and yearlings not being able to survive a salinity of over 9 ppt. The minimum dissolved oxygen during the spring and summer is 5 mg/l.

The black bullhead or black bullhead catfish (Ameiurus melas) is a species of bullhead catfish. Like other bullhead catfish, it has the ability to thrive in waters that are low in oxygen, brackish, turbid and/or very warm.[2] It also has barbels located near its mouth, a broad head, spiny fins, and no scales. It can be identified from other bullheads as the barbels are black, and it has a tan crescent around the tail. Its caudal fin is truncated (squared off at the corners).[3] Like virtually all catfish, it is nocturnal, preferring to feed at night, although young feed during the day. It generally does not get as large as the channel or blue catfish, with average adult weights are in the 1- to 2-lb range, and almost never as large as 4 lb. It has a typical length of 8-14 in, with the largest specimen being 24 in, making it the largest of the bullheads. It is typically black or dark brown on the dorsal side of its body and yellow or white on the ventral side.

The blackchin shiner is an abundant North American species of freshwater fish from the family Cyprinidae. Described by Edward Drinker Cope in 1865, it is not a well-known species. It is a close relative of the blacknose shiner. Chiefly occurring now in the Great Lakes and occasionally in upper Mississippi River drainages, the blackchin once ranged commonly as far south as Illinois and Ohio. This fish resides over sandy bottoms in cool waters that provide a lot of cover for the small minnow. Omnivorous, it eats worms and small arthropods as well as plant material. Blackchin shiners are unique because of their anatomical features, such as the black coloring, the incomplete lateral line, and a distinctive dental arrangement. Blackchin shiners have a thin strip of golden scales just above their black stripe. They also have scales on their backs and upper sides that have dark edges, which make them unique from other shiners. Another thing that makes this species of shiner unique, especially from the closely related bigeye shiner, is that blackchin shiners have an incomplete lateral line with a dusky spot above and below each sensory pore. All fins of blackchin shiners are transparent, and the underbelly is a pale cream shade. The scales of these fishes are thinner, flexible scales called bony-ridged scales. Blackchins have scales called cycloid scales, which are round and, compared to the scales of other fishes, smooth. These scales are a clue that this species is primitive in comparison to other teleosts, many of whom have ctenoid scales. For species of fish with either version of leptoid scales, the age of the fish can be determined by examining the pattern of ridges on a scale, similar to how tree trunk rings display the age of a tree.

The bluegill is a species of freshwater fish sometimes referred to as 'bream', 'brim', 'sunny', or 'copper nose'. It is a member of the sunfish family Centrarchidae of the order Perciformes. It is native to North America and lives in streams, rivers, lakes, and ponds. It is commonly found east of the Rockies. It usually hides around, and inside, old tree stumps and other underwater structures. It can live in either deep or very shallow water, and will often move from one to the other depending on the time of day or season. Bluegills also like to find shelter among aquatic plants and in the shade of trees along banks.Bluegills can grow up to 12 inches (30 cm) long and about 4 1⁄2 pounds (2.0 kg). While their color can vary from population to population, they typically have a very distinctive coloring, with deep blue and purple on the face and gill cover, dark olive-colored bands down the side, and a fiery orange to yellow belly. The fish are omnivores and will eat anything they can fit in their mouth. They mostly feed on small aquatic insects and fish. The fish play a key role in the food chain, and are prey for bass, other (sunfish), northern pike, walleye, muskies, trout, herons, kingfishers, snapping turtles, and otters.

The brassy minnow (Hybognathus hankinsoni) is a species of fish belonging to the family Cyprinidae. The family Cyprinidae consists of mainly freshwater minnows and carps. The fish gets its scientific name (Hybognathus hankinsoni) from the Greek word Hybognathus, meaning bulging jaw, and hankinsoni from the American scientist, T.L. Hankinson.It is commonly found throughout the northern United States and Canada. Range extends from the St. Lawrence River and Lake Champlain drainages, throughout the Great Lakes and Northern United States and into Alberta and British Columbia. he brassy minnow typically lives in cool, slow moving streams and creeks that have sand, mud or gravel bottoms overlaid with organic sediment. They are also found in overflow ponds near rivers, boggy lakes, brackish tidal waters, and ditches with weedy bottoms. They live in water with a large range of pH's, and are able to survive at low oxygen levels, displaying high levels of environmental tolerance.The water can be clear or turbid. Brassy minnows appear to do better in habitats with minimal predators, or those that have structure for them to hide in, as they are very susceptible to predation.

The brown bullhead (Ameiurus nebulosus) is a fish of the family Ictaluridae that is widely distributed in North America. It is a species of bullhead catfish and is similar to the black bullhead (Ameiurus melas) and yellow bullhead (Ameiurus natalis). It was originally described as Pimelodus nebulosus by Charles Alexandre Lesueur in 1819, and is also referred to as Ictalurus nebulosus. The brown bullhead is also widely known as the 'mud pout', 'horned pout', 'hornpout', or simply 'mud cat', a name also used with the other bullhead species. The brown bullhead is important as a clan symbol of the Ojibwe people. In their tradition, the bullhead or wawaazisii is one of six beings that came out of the sea to form the original clans. Brown bullheads typically live between six and eight years, but have been recorded as old as fifteen in captivity. The species spawns between April and June. For the duration of each breeding season, females will be monogamous. There are no consistent behaviors of mate attraction. The females lay eggs in dark, shallow locations such as under rocks and inside logs, where they are externally fertilized by the male. The fish face opposite one another during the fertilization process. Nests are primarily created by females, but the eggs are protected by both sexes. The eggs usually take six days to hatch, but may take up to 13 days. Female brown bullheads will continue to guard their offspring for a while following their hatching. Both parents generally care for their offspring for an additional five days after the eggs hatch. Adults, both male and female, will reach sexual maturity around age three, and can produce between 10 and 10,000 offspring in their lifetime. Brown bullheads have occasionally been recorded eating their own eggs.

The burbot (Lota lota) is the only gadiform (cod-like) freshwater fish. It is also known as bubbot, mariah, freshwater ling, the lawyer, coney-fish, lingcod, freshwater cusk, and eelpout. The species is closely related to the marine common ling and the cusk. It is the only member of the genus Lota. For some time of the year, the burbot lives under ice, and it requires frigid temperatures to breed.With an appearance like a cross between a catfish and an eel, the burbot has a serpent-like body, but is easily distinguished by a single barbel on the chin.[5] The body is elongated and laterally compressed, with a flattened head and single, tube-like projection for each nostril. The mouth is wide, with both upper and lower jaws having many small teeth. Burbot have two soft dorsal fins, with the first being low and short, and the second being much longer. The anal fin is low and almost as long as the dorsal fin. The caudal fin is rounded, the pectoral fins are fan-shaped, and pelvic fins are narrow with an elongated second fin ray. Having such small fins relative to body size indicates a benthic lifestyle with low swimming endurance, unable to withstand strong currents.

The central mudminnow (Umbra limi) is a small fish in the family Umbridae of the order Esociformes. It is found in central and eastern North America in productive waters. It is fairly tolerant of low oxygen concentrations and, as a result, it is sometimes the only, or one of a very few, fish species present in waters susceptible to winter or summer kill. The central mudminnow lives in slow-moving water around ponds, lakes, and streams in central North America, and ranges in length from 51–102 mm.It burrows tail-first in mud and can tolerate low oxygen levels, allowing it to live in waterways unavailable to other fishes. Its coloration matches this habitat, being brownish above with mottled sides and a pale belly. It is eaten by many species of fish such as grass pickerel, sunfishes, northern pike, and catfishes; it is also preyed upon by birds, foxes, and snakes when caught out of water. According to Paszkowski and Tonn, mudminnows perform better in environments with other fish species than in environments with just mudminnows, because the 'interspecific interactions override a similar contribution for the mudminnow, which is regarded as a fugitive species'. Central mudminnows are known to eat a large variety of zooplankton and benthic and epiphytic macroinvertebrates. Adults are also known to feed energetically in the winter months on littoral fish. One experiment conducted by Colgan and Silburt resulted in mudminnows typically feeding more on benthic than planktonic resources, with zooplankton making up only 0.7 of 511 items found in the stomach. This mudminnow uses a modified gas bladder to breathe air pockets trapped between the ice and water during the winter to feed and stay active.Umbra limi is a widely distributed species that inhabits many freshwater systems such as lakes, streams, and wetlands near the littoral zone, or near the shore, and around dense cover in central North America west of the Appalachian Mountains, including the St. Lawrence River, Great Lakes, Hudson Bay (Red River, and the Mississippi River basins from Quebec to Manitoba and south to central Ohio, western Tennessee, and northeastern Arkansas. The central mudminnow has also been introduced into many of the tributaries in Connecticut and Massachusetts. Their habitats being marshy lands and rivers are under attack by human development and contact constantly and is likely causing a decline in their populations.

The chestnut lamprey (Ichthyomyzon castaneus) is a species of lamprey. The chestnut lamprey has a maximum length of around 345 millimetres (13.6 in), 325 millimetres (12.8 in) in Canada, with dark grey to olive skin color, blue-black after spawning, and with five to eight bicuspid laterals around its mouth. The chestnut lamprey is closely related to the nonparasitic southern brook lamprey, and the two have been termed a paired species. The range of the chestnut lamprey extends from Lake Winnipeg and the Hudson Bay down the Mississippi River to the Central and Eastern United States; this includes any large lakes or reservoirs where large host fish are present. In Canada, the chestnut lamprey has been found in Saskatchewan, Manitoba, Ontario, and Quebec.

The common carp or European carp (Cyprinus carpio) is a widespread freshwater fish of eutrophic waters in lakes and large rivers in Europe and Asia. The native wild populations are considered vulnerable to extinction by the International Union for Conservation of Nature (IUCN), but the species has also been domesticated and introduced (see aquaculture) into environments worldwide, and is often considered a destructive invasive species, being included in the list of the world's 100 worst invasive species. It gives its name to the carp family, Cyprinidae. Although tolerant of most conditions, common carp prefer large bodies of slow or standing water and soft, vegetative sediments. As schooling fish, they prefer to be in groups of five or more. They naturally live in temperate climates in fresh or slightly brackish water with a pH of 6.5–9.0 and salinity up to about 0.5%, and temperatures of 3 to 35 °C (37–95 °F).[The ideal temperature is 23 to 30 °C (73–86 °F), with spawning beginning at 17 to 18 °C (63–64 °F); they easily survive winter in a frozen-over pond, as long as some free water remains below the ice. Carp are able to tolerate water with very low oxygen levels, by gulping air at the surface.Common carp are omnivorous. They can eat a herbivorous diet of aquatic plants, but prefer to scavenge the bottom for insects, crustaceans (including zooplankton), crawfish, and benthic worms. An egg-layer, a typical adult female can lay 300,000 eggs in a single spawn. Although carp typically spawn in the spring, in response to rising water temperatures and rainfall, carp can spawn multiple times in a season. In commercial operations, spawning is often stimulated using a process called hypophysation, where lyophilized pituitary extract is injected into the fish. The pituitary extract contains gonadotropic hormones which stimulate gonad maturation and sex steroid production, ultimately promoting reproduction.

Semotilus atromaculatus, known as the creek chub or the common creek chub, is a small minnow, a freshwater fish found in the eastern US and Canada. Differing in size and color depending on origin of development, the creek chub can usually be defined by a dark brown body with a black lateral line spanning horizontally across the body. It lives primarily within streams and rivers. Creek Chubs attain lengths of 2-6 inches with larger specimens of up to 12 inches possible. The genus name Semotilus derives from the Greek word sema (also known as dorsal fin), and atromaculatus comes from the Latin word 'black spots'. A fish which can withstand many different environments, the creek chub's current range is the eastern two-thirds of the US and southeastern Canada. It can quickly adapt to different extreme environments, and can live on many different foods. Documented to span throughout the Great Lakes surrounding Wisconsin, and into Minnesota, this species has been described as plentiful. However, reports of this species have fallen throughout Wisconsin and the Great Lakes, suggesting a decline in its population in these regions. Though populations have been declining within the Great Lakes, they have been continually documented throughout small and medium rivers and streams. Thriving in small stream environments, the creek chub gravitates toward areas of weeds to appear secure and avoid predation. Varying in environments containing a multitude of substrates, they have been documented over gravel, sand, silt, rubble, mud, boulders, clay, bedrock and detritus bottoms. This fish actually prefers the stream or river environment compared to that of a lake, as they have been recorded in streams far more than lakes. Of over 440 individuals caught, only 9 were from lakes, and when limiting the locations to solely lakes, only six individuals were caught

The emerald shiner is one of hundreds of small, silvery, slender fish species known as shiners. The identifying characteristic of the emerald shiner is the silvery emerald color on its sides. It can grow to 3.5 inches in length and is found across North America from Canada to the Gulf of Mexico, commonly in large, deep lakes and rivers, though sometimes in smaller bodies of water as well. It feeds on small organisms such as zooplankton and insects, congregating in large groups near the surface of the water. It is a quite common fish and is often used as a bait fish. Maximum size is 89–127 mm. Females are larger than males. Live emerald shiners are a bright, iridescent, silvery green with a silver mid-lateral band. The back and upper sides are emerald greenish to straw colored, and the ventral side of the fish is a silvery white color. The dorsal scales have pigmented margins and clear centers. The area between the nostril and the eye lacks pigment, and the lips are pigmented medially and continues to halfway down the midline of the lower jaw. The dorsal, caudal, and leading rays of the pectoral fins are lined with pigment, but the remaining fin rays and membranes are clear. The underside of the opercle are gray. Live emerald shiners are a bright, iridescent, silvery green with a silver mid-lateral band. The back and upper sides are emerald greenish to straw colored, and the ventral side of the fish is a silvery white color. The dorsal scales have pigmented margins and clear centers. The area between the nostril and the eye lacks pigment, and the lips are pigmented medially and continues to halfway down the midline of the lower jaw. The dorsal, caudal, and leading rays of the pectoral fins are lined with pigment, but the remaining fin rays and membranes are clear. The underside of the opercle are gray.

The finescale dace is a species of freshwater fish in the family Cyprinidae of the order Cypriniformes. It is native to the northern portions of Minnesota. Finescale dace gets its name from the fine scales running along its body. The species is characterized by its large, blunt head and dark lateral bands running parallel to the length of its bronze and black body. The finescale dace occupies the regions ranging across the southern and northwest parts of Canada to Minnesota areas and more southward to the areas near the Great Lakes Basin. The populations have been shown to inhabit regions of Minnesota, including Brule Lake, as well as those bodies of water occupying the Lake Superior drainage areas of St. Louis and Cook counties.

The fourhorn sculpin (Myoxocephalus quadricornis) is a species of fish in the family Cottidae. It is a demersal fish distributed mainly in brackish arctic coastal waters in Canada, Greenland, Russia, and Alaska, and also as a relict in the boreal Baltic Sea. There are also freshwater populations in the lakes of Norway, Sweden, Finland and Karelia (NW Russia) and in Arctic Canada (Nunavut and Northwest Territories).The fourhorn sculpin has a large knobbly head with protruding lips and four bony protuberances, though the latter are not present in freshwater, lake forms of this fish. The pectoral fins are large and rounded. Freshwater forms resemble the Alpine bullhead and European bullhead but can be distinguished from them by the fact that the dorsal and anal fins terminate further forward giving a greater length to the caudal peduncle. The head, body and fins are brownish, mottled and barred with darker colour. The belly of the male is yellowish-brown while that of the female is whitish. In the sea this fish reaches 20 to 30 cm (8 to 12 in) but in lakes it seldom exceeds 15 cm (6 in) e fourhorn sculpin feeds on bottom-dwelling invertebrates and fish eggs. It breeds in winter between November and March and the male tends the eggs. He digs a hollow in the substrate into which the female lays a batch of eggs. He then remains on guard, fanning the eggs with his fins throughout the hundred-day incubation period.

The golden redhorse( Moxostoma erythrurum) is a species of freshwater fish endemic to Ontario and Manitoba in Canada and the Midwestern, southern, and eastern United States. It lives in calm, often silty or sandy waters in streams, small to large rivers, and lakes. A bottom-feeder, it feeds on microcrustaceans, aquatic insects, detritus, algae, and small mollusks. The golden redhorse spawns in the spring. Golden redhorses average around 12-18 inches long and weigh between 1-2 pounds, although some can reach up to 26 inches and 4-5 pounds. The golden scales decorating its sides gave the fish its name. They have olive colored backs, white bellies, and slate gray tail fins. Their body is fusiform in shape, allowing them to fight against currents in streams to capture their prey. The mouth of the fish is in the inferior position. The dorsal fin is slightly concave and the caudal fin is notched. It has a single anal fin and paired pelvic and pectoral fins. The pelvic fins are in the abdominal position, while the pectoral fins are located in more of a thoracic position. It has a lateral line system consisting of 39 to 42 scales which is used to detect movement and vibrations in the surrounding water. Golden redhorses can be found in freshwater streams, creeks, and rivers with varied substrates. In pools they are generally found over sand and silt. Occasionally they have been seen living in lakes or larger reservoirs that are fed by a stream or river. Compared to other redhorse species the golden redhorse is not very sensitive to poor environmental conditions.The diet of the golden redhorse consists of a variety of small, aquatic creatures. They consume larval insects, small mollusks, microcrustaceans, and other aquatic invertebrates. Like most other members of the sucker family, Catostomidae, detritus and algae are also staples of the golden redhorse's diet. It is a bottom-feeding species that is able to use its protrusible mouth to suck up food objects from the stream bed

The goldeye (Hiodon alosoides) is a relatively small, opportunistic foraging freshwater fish of the family Hiodontidae (order Osteoglossiformes). Goldeyes are deep bodied, with small blunt heads and rounded snouts. They have many small sharp teeth on their jaws and tongues. Their large yellow eyes are adapted to low light and turbid water conditions allowing them to be essentially nocturnal. Goldeyes have dark-blue to blue-green backs, silvery sides, white bellies and brown edges to their scales giving them a slightly tan coloured appearance. They are mainly surface feeders, consuming aquatic insects, snails, minnows, other small fish and any other edible organisms they encounter.

The hornyhead chub (Nocomis biguttatus) is a small species of minnow in the family Cyprinidae of order Cypriniformes. It mainly inhabits small rivers and streams of the northern central USA, up into Canada. The adults inhabit faster, rocky pools of rivers. The Hornyhead chub is moderate in size and slightly subterminal with an inconspicuous barbel in corner of mouth. This fish has no teeth. A body pattern of a back olive brown in color, with its sides having silvery color, and a belly of white. It also has a dark lateral stripe and a spot at the base of the tail, which is faint or absent in some adults. Fins contain decorative markings. Its body shape is fusiform and robust, round in cross-section. Typical adult size is 100–150 mm TL (4–6 in), with a maximum of about 225 mm (9 in). It has a forked tail and a single relatively short dorsal fin with 8 rays and without spines. Its pelvic fins are abdominal and has no adipose fin. Lastly, its anal fin with 7 rays has no spines. Its distinguishing characteristics are its moderately slightly subterminal mouth, and its defining inconspicuous barbel in the corner of its mouth. It also uniquely has 38-48 lateral line scales and a dark lateral stripe and caudal spot. Breeding adults have numerous large pointed tubercles on the top of their heads, smaller tubercles on their pectoral fins and a red or orange spot on the upper opercle behind their eyes. However juveniles look similar to adults, but have more obvious lateral stripes and caudal spots, and their tails are typically more reddish than the adult's tail. Adults can grow to 11 cm or more, and males commonly grow tubercles on their head during spawning season.

Kokanee are silvery in color until they are ready to spawn, at which time they become reddish. They do not grow as large as sockeye- their ocean traversing siblings. They can vary significantly in size depending on how densely populated the waterbody is. Since they are filter feeders, their populations can quickly expand and contract with the availability of food. Kokanee can be found at all depths of cold, clear lakes and reservoirs in several parts of the state. They will change which depth they are at depending on water temperature. They are a challenging fish to catch as they eat mostly zooplankton, but they will take both flies and lures. Once caught, they make great table fare.

The lake trout is a freshwater char living mainly in lakes in northern North America. The lake trout is prized as a game fish and a food fish. Those caught with dark coloration may be called mud hens. Lake trout are the largest of the chars; the record weighed almost 102 pounds (46 kg) (netted) with a length of 50 inches (130 cm), and 15–40-pound (6.8–18.1-kilogram) fish are not uncommon. The average size is 24–36 inches (61–91 centimeters). Lake trout are known to hybridize in nature with the brook trout; such hybrids, known as 'splake,' are generally sterile, but self-sustaining populations exist in some lakes. Splakes are also artificially propagated in hatcheries and then stocked into lakes to provide sport-fishing opportunities.

The largemouth bass (Micropterus salmoides) is a carnivorous freshwater gamefish in the Centrarchidae (sunfish) family, a species of black bass generally native to eastern and central North America, in Canada, United States and northern Mexico, but widely introduced elsewhere.The largemouth bass is an olive-green to greenish gray fish, marked by a series of dark, sometimes black, blotches forming a jagged horizontal stripe along each flank. The upper jaw (maxilla) of a largemouth bass extends beyond the rear margin of the orbit. The largemouth is the largest of the black basses, reaching a maximum recorded overall length of 29.5 in (75 cm) and a maximum unofficial weight of 25 pounds 1 ounce (11.4 kg).Sexual dimorphism is found, with the female larger than the male. Average lifespan in the wild is 10 to 16 years.

The longnose dace (Rhinichthys cataractae) is a freshwater minnow native to North America. Rhinicthys means snout fish (reference to the long snout) and cataractae means of the cataract (first taken from Niagara Falls). Longnose dace are small, typically less than 100 mm and characterized by their fleshy snout that protrudes past the mouth. They are well adapted for living on the bottom of fast-flowing streams among stones. Longnose dace eat algae and aquatic insects and are important forage minnows for larger predatory fish. Longnose dace can be mistaken for suckers because of their subterminal 'sucker-like' mouth. However, longnose dace (like all members of the family cyprinidae) lack small fleshy projections, called papillae, on their mouths. Juveniles have a black lateral line that extends from the beginning of the eye to the caudal fin that fades as the fish matures. The lateral line in juveniles is not present in all populations. In adults, the dorsal side is dark green to black, the lateral side is darkish to silvery with mottling often present, and the ventral side is pearly. Both adult males and females may have bright orange-reddish colouration at the base of pectoral, pelvic, and anal fins and on the upper lip. This colouration is typically associated with breeding males in the subspecies Rhinichthys catarace catarace, but the validity of this subspecies has yet to be confirmed. Museum specimens of females also show intense orange-reddish colouration at the base of the fins and upper lip, therefore colouration is not an accurate predictor of sex. The maximum length of longnose dace is 170 mm, but they are usually less than 100 mm.

The mimic shiner (Notropis volucellus) is a species of North American cyprinid freshwater fish in the genus Notropis. The genus Notropis is commonly known as the eastern shiners. It is native to areas of the Hudson Bay drainage, Great Lakes drainage, much of the Mississippi River basin including areas of Tennessee, Virginia, North Carolina, and regions of the Gulf of Mexico extending from Mobile Bay to the drainage of Texas. However, this particular species can be found in other places such as the Atlantic Coast drainage in Connecticut and Housatonic rivers. The Body of Mimic shiner is slender and compressed laterally. Snout is broad, rounded, and barely overhangs the small, slightly upturned mouth. Eyes are large. Scales particularly on the back and upper sides are dark edged; scales on forward part of lateral line are taller and narrower than elsewhere. Silvery sides have a faint, dusky lateral stripe which is more evident and thickest near the tail. Fins are clear. There is dark pigmentation around the anus and base of the anal fin. Coloration: Back is yellowish-olive; sides are silvery; underside is silvery-white. Size: Average about 2-3 inches. This is a fish of sandy pools in small to large rivers and some lakes. The mimic shiner is not a widely distributed species in Vermont but is fairly common in Lake Champlain and the Connecticut Rive

Mottled sculpin: sculpin comes from the Latin word for 'sea scorpion' and mottled refers to the dark blotches on the body.Mottled sculpins occur primarily in the Rainy River, Lake Superior, St. Croix River, and Mississippi River (upper and lower) drainages. They also are known from the Otter Tail and Clearwater rivers in the Red River drainage. In streams they inhabit small, clear streams and large lakes that have rocky shores. They occupy both riffle and pools over sand, gravel, boulders, or limestone. Mottled sculpins favor clear water with some form of shelter (for example boulders or vegetation) to use as hiding spots. Common associates of mottled sculpins include white suckers, creek chubs, brook sticklebacks, and pearl dace, to name a few. Minnesota mottled sculpins can get as big as 130 mm (about 5 in), but lengths of 75-90 mm (3-3.6 in) is more typical. Both sexes reach the age of 3 years. Very rarely one makes it to 4 years old. Since this fish is commonly a benthic (bottom dweller), they eat things that are found on the bottom. Diets vary from streams to lakes. In streams, aquatic insect larvae and sideswimmers are more common. In lakes, copepods, waterfleas, leeches, and algae are added. Occasionally, fish eggs and even small fish are found in mottled sculpin stomachs. In trout streams, mottled sculpins are frequently eaten by large brook trout and brown trout. In other streams, they are eaten by young northern pike. They are eaten by smallmouth bass and walleye in northern lakes. American mergansers also prey on them. Humans do not eat them, but some anglers use them as bait. Mottled sculpins breed at water temperatures of 5-16° C (63-74° F), which is April and May depending on how far north the population is.

The ninespine stickleback (Pungitius pungitius), also called the ten-spined stickleback, is a freshwater species of fish in the family Gasterosteidae that inhabits temperate waters. It is widely but locally distributed throughout Eurasia and North America. Despite its name, the number of spines can vary from 8 to 12. The body of the ninespine stickleback tapers to a very narrow caudal peduncle and the caudal fin is fan-shaped. The body is less deep and more elongated than that of the three-spined stickleback with a thinner and longer caudal peduncle, but the best way of distinguishing these two species is the number of spines in front of the dorsal fin which, for this species, varies from seven to twelve although nine is the commonest number. This species does not have scales but there is a group of small bony plates on the narrowest part of the caudal peduncle at the lateral line. The mouth points upwards in this species. It is generally greyish or olive-brown with silvery flanks irregularly barred or blotched with darker colour. During the breeding season, the males develop a black area around the pelvis and the pelvic spines become white. The eyes are dark with a gold ring around the pupils. The ninespine stickleback lives in streams, lakes, ponds and rivers and favors thick submerged vegetation, as its small spines do not offer much protection. Like the three spined stickleback, they have a series of scutes or bony plates along the lateral line but, in freshwater populations, these are frequently reduced in number with a gap between the anterior and posterior plates. During the breeding season (April to July), the male builds a nest suspended on a piece of waterweed, about an inch or so above the substrate at the bottom. The female is attracted by the male and she lays eggs inside the nest, but then departs, leaving parental care to the male. The male guards these eggs and the young fry when they hatch. Then, when they have their spines, he drives them away to look after themselves.

Northern pike are circumpolar in the freshwater world of the northern hemisphere. Adult northern pike are usually solitary and highly territorial. Spawning adults will begin to move inshore or upstream to marsh areas to spawn as soon as the ice begins to break up or thaw in early spring. Spawning will normally occur during daylight hours in shallow quiet areas with a weed bottom. Male northern pike begin courting the female pike by nudging her head region. The male northern pike then follows this head nudging behavior with multiple thrusting movements, to entice the female to extrude her eggs. As the female begins to release her eggs, the male pike will simultaneously begin to release his milt and fertilize the eggs as they settle down to the bottom. The fertilized eggs will then hatch sometime in the next two to five weeks. Upon hatching, young pike will attach themselves to freshwater weeds and live off of their yolk sac while their mouths are still developing. Upon full development of their mouths, the young pike will feed on zooplankton and then graduate to insects and ultimately other fish and other prey.

The Allegheny pearl dace (Margariscus margarita) is a species of cyprinid fish. It is demersal, freshwater fish, with a dark green back and silvery body. This species is omnivorous, consuming algae, as well as arthropods. Peal dace's range spans southern Canada and the northern United States. While not considered endangered at the federal level in the United States, several states either consider this species endangered or threatened; it faces threats of habitat destruction and invasive species. is a bottom-dwelling freshwater fish that has been recorded to reach sizes of 16 cm (6.3 in), however, it does not commonly grow beyond about 9.3 cm (3.7 in). The body is long with small eyes and mouth.There are eight rays each in the dorsal fin, anal fin, and pelvic fins. The dorsal side is dark green in colour, with silvery flanks and a grey or white ventral side. Between late autumn and summer, males may have a brilliant orange-red stripe on the flanks, below the lateral line. This species is omnivorous: its diet comprises algae, as well as arthropods, such as chironomids and water fleas. Peal dace spawns in the spring. This species typically reaches sexual maturity at one year. This species inhabits North America, in southern Canada and the northern United States. It can be found in the Mississippi River, Hudson Bay, and the Great Lakes.

The quillback (Carpiodes cyprinus), also known as the quillback carpsucker, is a type of freshwater fish of the sucker family widely distributed throughout North America. It is deeper-bodied than most suckers, leading to a carplike appearance. It can be distinguished from carp by the lack of barbels around the mouth. The quillback is long-lived, with age beyond 50 years documented. The quillback is a large, ectothermic, deep-bodied fish found throughout North America. It has a small head, humped back and deeply forked caudal fin. The compressed body of the quillback makes it look flattened when viewed from the side. The quillback has a subterminal mouth with no barbels, and no nipple-like protrusions on the bottom lip. It has large, reflective, silver cycloid scales that are responsible for giving the quillback its characteristic silver color. They have a white belly with yellow or orange lower fins. The tail and dorsal fin are usually gray or silver. The quillback gets its name from the long quill that is formed via the first several fin rays of the dorsal fin. Quillback are typically 15–20 inches on average, weighing between 1 and 4 pounds. However, they can grow up to 26 inches and weigh 10 pounds. The quillback has a nearly straight, hyper-sensitive lateral line, composed of at least 37 lateral line scales. This helps the fish locate predators and prey. The quillback is found throughout much of North America, from Saskatchewan to Florida, and from South Dakota to Alabama. The quillback occupies temperate, freshwater habitats. This includes many streams, lakes, channels and rivers. They prefer water that is clear, slow moving, highly productive and moderately deep. The quillback can commonly be found in the Hudson Bay, the Mississippi River basin, the Great Lakes, and drainages from the Delaware, Apalachicola, and Pearl rivers.They often comprise a large portion of the biomass of warmwater rivers, but they are very difficult to catch with traditional American angling methods.The quillback carpsucker is closely related to the highfin carpsucker and the river carpsucker. All three species are rarely caught by anglers due to their feeding habits, but they have been caught occasionally on worms, minnows, and artificial lures.

Rainbow trout (Oncorhynchus mykiss) are not native to the UK – our only native trout is the brown trout (Salmo trutta). The native range of rainbow trout borders the northern Pacific ocean from America to Russia but they have been introduced to many countries, including the UK. They are also very widely farmed both as a table fish and to stock lakes and some rivers as a sport fish.Both brown and rainbow trout have the ability migrate to sea, returning to spawn in freshwater. Rainbow trout that spend part of their lives at sea are called steelhead, brown trout that go to sea are called sea trout (or sewin or peel or many other local names). But for both species, there are lots of life history strategies that see them moving around within rivers, between rivers and lakes and between freshwater, brackish and salt water. Rainbow trout are so called because they may have a very distinct red or pink lateral line. They are often called ​‘redband trout’, although strictly speaking this description relates to rainbow trout from the Columbia, MacLeod or Great basins of the western USA.

River shiners historically occurred in large rivers throughout the Arkansas River basin, including Arkansas, Cimarron, and Canadian rivers in Oklahoma. The Arkansas River shiner only inhabits wide and shallow prairie rivers with sandy bottoms, though it uses various microhabitats within these systems throughout its life cycle. These shiners often congregate in schools on the side of sandbars and ridges and rarely occur in the open water of the main river channel. This fish is a small, robust, streamlined minnow with light silver to tan coloration. Approximately two inches in length, it can be distinguished from similar species by its proportionally small eye and a dark spot at the base of the caudal (tail) fin.

The round whitefish (Prosopium cylindraceum) is a freshwater species of fish that is found in lakes from Alaska to New England, including the Great Lakes.It has an olive-brown back with light silvery sides and underside and its length is generally between 9 and 19 inches (23 and 48 cm). They are bottom feeders, feeding mostly on invertebrates, such as crustaceans, insect larvae, and fish eggs. Some other fish species, like white sucker in turn eat their eggs. Lake trout, northern pike and burbot are natural predators. Other common names of the round whitefish are Menominee, pilot fish, frost fish, round-fish, and Menominee whitefish. The common name 'round whitefish' is also sometimes used to describe Coregonus huntsmani, a salmonid more commonly known as the Atlantic whitefish. While it was once common, numbers have been decreasing in the last century due to a number of possible causes. The round whitefish is now protected in some states, such as New York, under the Endangered Species Act from harvest or possession. In Alaska, the whitefish is occasionally caught by anglers, but in general, the fish is not sought after, is rarely caught, since it is a bottom feeder; and the species is not protected.

The sauger (Sander canadensis) is a freshwater perciform fish of the family Percidae which resembles its close relative the walleye. They are members of the largest vertebrate order, Perciformes.They are the most migratory percid species in North America.Saugers obtain two dorsal fins, the first is spiny and the posterior dorsal fin is a soft-rayed fin. Their paired fins are in the thoracic position and their caudal fin is truncated which means squared off at the corners, a characteristic of the family Percidae. Another physical characteristic of Saugers are their ctenoid scales which is common in advanced fishes. Saugers have a fusiform body structure, and as a result saugers are well adapted predatory fishes and are capable of swimming into fast currents with minimal drag on their bodies. They may be distinguished from walleyes by the distinctly spotted dorsal fin, by the lack of a white splotch on the caudal fin, by the rough skin over their gill, and by their generally more brassy color, or darker (almost black) color in some regions. The average sauger in an angler's creel is 300 to 400 g (11 to 14 oz) in weight. Sauger are most likely to be found in large rivers with deep pools with depths greater than 0.6 m. Pools with depths less than 0.6 m are not likely to yield saugers. They encounter a variety of habitats because of their migratory tendencies. They are usually found in natural rivers because they have more abundant pools and their flow regime has not been altered by dams or diversions. They are still common in impounded river systems. Diversions and dams affect habitat and spawning areas of Saugers. Saugers are usually found in areas with high turbidity, low channel slope, low stream velocity, and deep water.[4] Saugers tend to select pools with sand and silt substrates, and habitat features that provide cover from the river current.

Myoxocephalus scorpius, typically known as the shorthorn sculpin or bull-rout, is a species of fish in the family Cottidae. It is a demersal species of the Northern Atlantic and adjacent subarctic and Arctic seas. The species has many English names that are used less frequently or in small parts of its range, including Arctic sculpin, daddy sculpin, European sculpin, father-lasher, goat sculpin, Greenland sculpin, guffy, horny whore, pig-fish, scully, scummy, short-spined sea scorpion and warty sculpin. It reaches maturity at 15–30 cm (6–12 in) in length and specimens from the Arctic and subarctic, which grow to the largest size, can reach up to 60 cm (24 in). The fish has a squat appearance, a large spiny head and a tapering body. It is a mottled grey-brown in colour but can be darker, including black as base coloring. It has a large mouth and spiny gill covers. The shorthorn sculpin is not venomous, but it can be mistaken for similar looking venomous fishes, notably scorpionfish.The shorthorn sculpin is found among seaweed or on rocky bottoms with mud or sand from 0 to 451 m (0–1,480 ft). Although primarily a marine species, it also occurs in brackish waters like the Baltic Sea. Like some other coldwater fish, it has antifreeze proteins, which allow it to survive at temperatures around or slightly below freezing. They feed on a wide range of demersal and benthic fishes and crustaceans. The shorthorn sculpin spawns in December through March, the eggs being laid on between rocks in a clump protected by the male. They usually hatch in five weeks.

The silver lamprey (Ichthyomyzon unicuspis) is a lamprey commonly found in the Northern and Central United States, as well as a large part of southern Canada. Its binomial name means 'sucking fish' in Greek and 'one-pointed' in Latin. The silver lamprey is a member of the Class Agnatha, sometimes referred to as cyclostomes (round-mouths). Other common names include: Bloodsucker, Blue Lamprey, Hitch-hiker, Lamper, Lamprey Eel. The silver lamprey should not to be confused with the sea lamprey (Petromyzon marinus), which has caused considerable damage to native fish populations in the Great Lakes region. Adult silver lampreys prefer the clear waters of large streams, rivers, and lakes. Adults migrate to nest in flowing water that has stoney or gravelly bottom material. When they hatch, the larvae move to slowly flowing areas initially with thick organic layers. As they grow in size, they begin to migrate to sandy environments where they will reside until they reach metamorphosis. The silver lamprey is an eel-like fish with an attenuate body composed of 49–52 clearly defined segments (i.e. myomeres, between the last gill slit and the anus). Silver lampreys possess a cartilaginous skeleton, and adults generally grow to a length of 12 inches and are silvery or bluish in color when spawning. Prior to spawning adults are often a dull brown or tan color. The dorsal fin is continuous, though it may be notched. The mouth is a jawless, sucking disc, with unicuspid teeth arranged in circular rows and is in the inferior position. When expanded, the mouth is wider than the lamprey's body. The lamprey's gills are arranged in a straight line immediately behind the eye, and a single nostril is located between the eyes. Larvae are a brown to tan all over have no eyes (instead they have eyespots) and are called ammocoetes. They also have seven gill openings and do not have any paired fins, they have only a long continuous fin runs from the dorsal to the ventral side. Ammocoetes also have no teeth and instead have an oral hood which houses skin extensions that help them filter particles out of the water as they draw it into their oral cavity.

The slimy sculpin, is a freshwater species of fish belonging to the family Cottidae, which is the largest sculpin family. They usually inhabit cold rocky streams or lakes across North America, ranging from the Great Lakes, southeast Minnesota, northeast Iowa, southwest Wisconsin and northeast Canada. Slimy sculpins have also been found roaming the cold streams of eastern Siberia. They are commonly confused with their closely related relatives, Mottled sculpin (Cottus bairdi), and with tubenose gobies who are both freshwater fishes as well. The slimy sculpin is a nocturnal fish that usually spends most of its time on the stream bottom and seeks shelter under rocks and logs, especially during spawning season. When it swims, it sometimes appears to be 'hopping' along the bottom because of its inefficient ability to swim. This is partly due to the absence of a swim bladder, which normally gives buoyancy to a fish. The fish has been studied in waters where there is current freshwater acidification. Sculpin were found to be less active and have lower rates of reproduction when found in these waters. For these reasons, slimy sculpin have been identified as a good indicator species for changes in acidification among lakes, ponds, and streams. Slimy sculpins often inhabit swift rocky-bottomed cold streams, oligotrophic lakes, and even brackish waters at a preferred temperature range of 9-14 °C. Nocturnally active fishes, they usually roam around in deeper waters ranging from 37–108 meters deep. During the breeding season, females often lay their eggs under sheltered areas like large objects such as rocks or tree roots found at the bottom of lakes or streams that males will guard.

The splake or slake is a hybrid of two fish species resulting from the crossing of a male brook trout and a female lake trout. The name itself is a portmanteau of speckled trout (another name for brook trout) and lake trout, and may have been used to describe such hybrids as early as the 1880s. Hybrids of the male lake trout with the female brook trout (the so-called 'brookinaw') have also been produced, but are not as successful. The intrageneric hybrid is of the genus Salvelinus and, hence, is most properly known as a char or charr. In some locales, the fish is referred to as the wendigo. Although the hybrid is genetically stable and is, theoretically, capable of reproducing, splake reproduction is extremely rare, for behavioural reasons, outside the hatchery environment. The only known natural reproduction has occurred in five lakes in Algonquin Provincial Park in Ontario, Canada and, in each case, only a handful of progeny were produced. Because splake typically do not reproduce, they are used as a sport fish in many lakes across the US. Fishery managers are able to control populations numbers due to the extremely poor spawning success rate. The fish possesses characteristics of both parent species. Splake exhibit higher growth rates than either parent species and can attain 46 cm (18 in) in length only two years after being planted as fingerlings (i.e., at 2½ years of age). By way of contrast, lacustrine brook trout would approach 25 cm (10 in) in length at a similar age and similarly aged lake trout would be expected to be less than 40 cm (16 in) long.Splake are considered 'easier to catch' than other salmonids and often live longer and fare better in certain situations. Hence, splake are well suited for stocking in a variety of coldwater lakes and ponds. The maximum size is about 9 kg (20 lb), but fish over 4 kg (9 lb) are rare and are considered trophies.

The spotfin shiner (Cyprinella spiloptera) is a species of ray-finned fish in the family Cyprinidae. It is a small sized fresh water fish found abundantly in many watercourse of North America. The spotfin shiner has a black blotch of pigment on the membrane between its last three rays of the dorsal fin; this spot may be obscure or faint in small spotfin shiners. They are deep-bodied and have a black vertical bar posterior to their operculum. Their mouths open in the terminal position, they have diamond-shaped scales, and each scale is outlined with black pigment. Breeding males become heavily pigmented and steel bluish in color during late spring and early summer, and they have ventral fins that also become dull yellow to bright yellow. The head of spotfin shiners are covered with small tubercles, and they feel rough, almost like sandpaper. Spotfin shiners also have 37-39 lateral line scales. Spotfin shiners have eight anal fin rays unlike its close relative, the satinfin. Cyprinela spiloptera inhabit all but one of the Great Lakes (Superior), and are found from the Saint Lawrence drainage, Quebec to the Potomac river drainage, Virginia. They also inhabit areas from Ontario and New York to North Dakota, as well as south to Alabama and eastern regions of Oklahoma. C. spiloptera are also located in isolated areas of the Ozark mountains. C. spiloptera are freshwater, benthopologic fishes that prefer temperate climates. They inhabit sand and gravel runs and pools of creeks, as well as small to medium rivers with clear, permanent flow.

Noturus flavus, the stonecat, is a North American freshwater catfish of the family Ictaluridae. The common name is due to its habit of hiding near or under stones in fast-moving water. Stonecats are small, slender, flat-headed catfishes, with the adipose fin keel-like and continuous with the caudal fin except for a shallow notch. While the dorsal and pectoral spines of most members of this family cause wounds that irritate, the stonecat has poison glands, particularly on the bases of the pectoral spines, that cause extreme pain similar to that of a wasp sting. The pectoral fin lacks any posterior serrae. Anal fin rays number 15 to 18, pectoral fin rays 9 to 11, and pelvic fin rays 8 to 10. The caudal fin rays number 55 to 67. The upper jaw projects beyond the lower jaw and the tooth pad on the upper jaw has a narrow, crescent-shaped extension on each side. The premaxillary band of teeth has lateral backward extensions. The skin of the stonecat is thick and is yellowish-brown in color. The sides of the head shade to yellow. The belly is whitish. The stonecat has two forms. In the Cumberland drainage in Tennessee, a scientifically undescribed form possesses two light bars (perpendicular to body length) on its nape. In other areas, a patch exists in place of the bars. In both forms, the stonecat has a white spot at the rear of the dorsal fin base and one on the upper edge of the caudal fin. The rear of the pectoral spine has either no or a few weak teeth. Stonecats live in freshwater environments, and are found from large creeks to small rivers. They occasionally are found in tiny creeks, or rivers as large as the Lower Mississippi. Stonecats occupy gently to fast-moving riffle areas with rocky substrates. They spend the majority of their time in moderate-moving, shallow riffles, but can also be found in deeper water (2 to 3 meters deep). Stonecat inhabit natural lakes, such as Lake Erie, where it prefers rock and gravel bars that are subject to significant wave action.The stonecat is a benthic, opportunistic feeder, using its sensitive barbels during the night to search for food on the river bottom. Stonecats eat a diversity of food items, such as aquatic insect larvae (e.g., mayflies), mollusks, minnows, fish eggs, isopods, amphipods, crayfish, plant material, worms and chilopods.The tadpole madtom is an invertivore, planktivore, but also feeds on particulate. A Common food source for the tadpole madtom are immature insects such as cladocera, ostracods, hyalella, and chironomids. Another popular food source is small crustaceans such as amphipods and isopods. Smaller fish feed more on small crustaceans while large fish tend to consume large prey such as worms and grass shrimp. Researchers in Wisconsin recorded the stomach contents of numerous tadpole madtoms and found an average diet consisting of 44% insects, 28.3% small crustaceans, 18.3% oligochaetes, 5.9% plants, 3% silt and debris, 0.1% snails, and 0.1% algae.

The three-spined stickleback is a fish native to most inland and coastal waters north of 30°N. It has long been a subject of scientific study for many reasons. This species can occasionally reach 8 cm (3.1 in), but lengths of 3–4 centimeters (1.2–1.6 in) at maturity are more common. The body is laterally compressed. The base of the tail is slender. The caudal fin has 12 rays. The dorsal fin has 10–14 rays; in front of it are the three spines that give the fish its name (though some individuals may have only two or four). The third spine (the one closest to the dorsal fin) is much shorter than the other two. The back of each spine is joined to the body by a thin membrane. The anal fin has eight to 11 rays and is preceded by a short spine. The pelvic fins consist of just a spine and one ray. The three-spined stickleback is found only in the Northern Hemisphere, where it usually inhabits coastal waters or freshwater bodies. It can live in either fresh, brackish, or salt water. It prefers slow-flowing water with areas of emerging vegetation. It can be found in ditches, ponds, lakes, backwaters, quiet rivers, sheltered bays, marshes, and harbors.

Percopsis omiscomaycus also known as the trout-perch, the grounder or the sand minnow, is one of two species in the family Percopsidae. They are freshwater fish that prefer clear to slightly turbid water. They are most often seen washed up on beaches and are rarely seen alive or correctly identified. They are found in rivers and lakes throughout North America. The trout-perch has been found at sizes of 20.0 centimetres (7.9 in) total length and the average total length is 8.8 centimetres (3.5 in). There are no distinguishing characteristics between males and females. They are overall silvery or nearly transparent in appearance with rows of dark spots on along the sides of their bodies both along their lateral line and above it. Their fins are almost entirely transparent. These fish have thick bodies with a long head, long snout, and a small mouth.They have a single dorsal fin containing 1–3 spines and 10–11 soft rays. They also have an adipose fin, similar to trout, which helps to distinguishes them from their look-alike species, the yellow perch and the walleye.Their tail or caudal fin is forked. Like most bony fishes, the trout-perch has thin, flexible plates of bone or leptoid scales. Their particular leptoid scales are ctenoid scales that are similar to the perch's. The trout-perch is found throughout North America, from Canada and Alaska to the Potomac river basin in Virginia. They are found in the Great lakes making them present in Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin. They are also found in the Mississippi River Basin which extends its range to include: Iowa, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana. They have also been spotted in North Dakota, Montana and West Virginia. Trout-perch prefer clear to slightly turbid water with sandy and gravely bottoms. They avoid shallow soft-bottomed areas. They participate in a daily migration, traveling from deep water during the day to shallow waters at night. This behavior is not only very important to their predators; the walleye, the northern pike, and the lake trout, but also in transporting nutrients in thermally stratified lakes. The nocturnal migration allows for foraging under the cover of night. The trout-perch feeds on a variety of small invertebrates including insect larvae and crustaceans. Juveniles feed on zooplankton. Larger adults will eat small fish such as the johnny darter.

The weed shiner (Notropis texanus) is a North American species of freshwater fish in the cyprinid genus Notropis. The weed shiner, Notropis texanus, is a member of the family Cyprinidae. It is a medium-sized minnow with a broad, dark lateral band down and a dark spot at the base of the caudal fin. The posterior 3-4 anal rays often have a dark pigment. Weed shiners have a somewhat compressed body, a large terminal to subterminal mouth, a gently rounded snout, and an eye diameter less than or equal to its snout length. The lateral line system is completely pored with 34-36 scales and is slightly decurved anteriorly. The dorsal surface of this fish tends to be olive-yellow with a silvery overlay and has dark-edged scales, giving off a checkerboard appearance. The ventral surface is white with silver tones.Weed shiners have a total of 6-8 gill rakers, 8 dorsal rays, 7 anal rays, 13-14 pectoral rays, and 8 pelvic rays. Weed shiners feed during the day, with peaks in activity after sunrise or during mid-afternoon. eed shiners are commonly found in the lower third of the water column in small to moderate sized streams of slow to moderate flow. They can be found in man-made ponds, reservoirs, and natural oxbow lakes. Despite its name, these fish are prevalent in both vegetated and non-vegetated waterways.Weed shiners spawn from March through September (sometimes early October), in water temperatures between 14-29° Celsius. Female weed shiners produce multiple clutches of eggs during the breeding season; therefore, it is hard to accurately estimate annual egg production.

The westslope cutthroat trout (Oncorhynchus clarkii lewisi), also known as the black-spotted trout, common cutthroat trout and red-throated trout is a subspecies of the cutthroat trout (Oncorhynchus clarkii) and is a freshwater fish in the salmon family (family Salmonidae) of order Salmoniformes. The cutthroat is the Montana state fish.This subspecies is a species of concern in its Montana and British Columbia ranges and is considered threatened in its native range in Alberta.The fish has teeth under its tongue, on the roof of the mouth, and in the front of the mouth. Westslope cutthroat are common in both headwaters lake and stream environments. They feed mainly on insects and zooplankton. The average length of the fish is about 8-12 inches (30 cm) and rarely exceeds 18 inches (46 cm). The skin has small dark freckle-like spots clustered towards the tail, and is mostly orange-hued. They can be distinguished from rainbow trout by the red, pink, or orange marking beneath the jaw (hence the name 'cutthroat').

The white crappie (Pomoxis annularis) is a freshwater fish found in North America, one of the two species of crappies. Alternate common names for the species include goldring and silver perch. USS Goldring is named for the fish. The genus name Promoxis refers to crappies' sharp operculum, while the species name annularis means 'having rings', i.e., it has vaguely vertical bars on the body. White crappies are morphologically similar to black crappies. They have 5–10 dark vertical bars along their bodies, rather than the randomly scattered spots like the black crappie. The white crappie has a silvery color with green or brown shades along its back, with dark lateral bars along its side, and a white belly. The dorsal fins of the white crappie starts farther back on the body than those of the black crappie. The anal fin is about the same size as the dorsal fin. The white crappie has six dorsal fin spines, whereas the black crappie has seven or eight dorsal fin spines.White crappies are also slightly more elongated than black crappies. The white crappie is a deep-bodied fish with a flattened body, or a depth that is one-third of the length of the fish. White crappies have spinous rays and ctenoid fish scales found in advanced teleosts. The exposed part of the scale has tiny tooth-like projections (cteni). Both species of crappies have a terminal mouth position with many small, conical teeth in two rows along the mouth and are called cardiform because they resemble a tool used for wool carding. Crappies belong to the family Centrarchidae in the infraclass Teleostei, which is one of three infraclasses in the class Actinopterygii. The white crappie rarely exceeds 2 pounds (0.91 kg), and typically lives 2–7 years. The species is generally about 9–10 inches (23–25 cm) in length as an adult.The current for all-tackle fishing world record for a white crappie is 2.35 kg (5.2 lb). White crappies can be found in large rivers, reservoirs and lakes. White crappies are more tolerant of turbid (murky) waters than black crappies. The white crappie usually outnumbers the black crappie in turbid waters and in areas with little rooted aquatic vegetation. White crappies are most commonly found in rivers and low-velocity areas such as pools and backwaters of rivers. They are most abundant in lakes and reservoirs larger than 5 acres. The white crappie can be found in the open water during the mornings and evenings, but during the day this species is found in shallower, quiet waters (6–12 feet (1.8–3.7 m) deep) surrounded by structure.

The yellow perch, commonly referred to as perch,or preacher is a freshwater perciform fish native to much of North America. The yellow perch has an elongate, oval body with a relatively long but blunt snout which does not reach past the tip of the lower jaw. Like most perches it has two separate dorsal fins.The anterior, or first, dorsal fin contains 12-14 spines while the second has 2-3 spines in its anterior followed by 12-13 soft rays. The anal fin has 2 spines and 7-8 soft rays. The upper part of the head and body varies in colour from bright green through to olive or golden brown. Although typically they are golden yellow. The colour on the upper body extends onto the flanks where it creates a pattern of 6-8 vertical bars over a background colour of yellow or yellowish green. They normally show a blackish blotch on the membrane of the first dorsal fin between the rearmost 3 or 4 spines.The colour of the dorsal and caudal fins vary from yellow to green while the anal and pelvic fins may be yellow through to silvery white. The pectoral fins are transparent and amber in colour. The ventral part of the body is white. The juvenile fish are paler and can have an almost whitish background colour. The maximum recorded total length is 50 centimetres (20 in). although they are more common;y around 19.1 centimetres (7.5 in), and the maximum published weight is 1.9 kilograms (4.2 lb). Yellow perch are only found in North America; they are native to the Arctic and Atlantic Oceans, and the Great Lakes-St. Lawrence River and Mississippi River basins. In Canada, its native range extends throughout Nova Scotia and Quebec north to the Mackenzie River. It also is common in the northwest to Great Slave Lake and west into Alberta. It is not native to any other areas of Canada. In the United States, the native range extends south into Ohio and Illinois, and throughout most of the northeastern United States. It is also considered native to the Atlantic Slope basin, extending south to the Savannah River. There is also a small native population in the Dead Lakes region of the Apalachicola River system in Florida.