|Langston University Aquaculture|
Identification and Natural History
By Kenneth Williams
The first question a pond owner often must answer before developing a pond management plan is what kind of fish are in my pond. This brief identification guide to common fish species found in ponds should help answer that question.
A brief discussion of species life history, diet, and habitat are also included as are comments on species suitability for pond stocking and species willingness to accept commercially prepared fish feeds. Fish are grouped under their scientific family name. Common and scientific names are given for each species.
The figure below illustrates common parts of fish external anatomy used in describing and distinguishing species.
Family: Centrarchidae, The sunfish, black basses and crappie
The sunfish are a large family of spiny rayed fishes native to North America. Many species of sunfishes such as largemouth, bass, bluegill, green sunfish, red ear sunfish, and long ear sunfish can be found in the still pools of streams and in lakes and ponds. Other sunfish, like the smallmouth bass, prefer flowing streams.
Many of these species are commonly lumped together and called perch. This is incorrect. The log perch, walleye and sauger are the only true perch found in Oklahoma. The common yellow perch is found in waters generally north of Iowa.
Smaller fish are found in shallow water near weed beds or other shaded, protective cover. In general, larger fish will be found in deeper water. Sunfishes are mostly omnivorous and will eat any animal that will fit in their mouths.
Lepomis macrochirus - bluegill
Identification: 6-8 fairly distinct vertical olive bars on the side of the fish. These bars are lighter or darker depending on sex of the fish, age and over-all coloration. The throat of males, particularly in spring and early summer is bright orange. Females and young have more nondescript silver-blue coloration. Bluegill have a distinctive, black rectangular "earflap" at the outer edge of the operculum.
Habitat: Bluegill live in relatively shallow water near weed beds and the shoreline. Larger fish are found in deeper water, usually 5 or more feet deep. The bluegill is abundant in lakes and
streams and is one of the most commonly stocked fish in farm ponds.
Natural Diet: Insects and insect larvae constitute a large portion of the bluegill diet. Small crayfish and snails are also important. The young feed on zooplankton. Midge larvae make up a high percentage of the bluegill diet. Bluegill will consume plants when animal diet items become scarce. They will also learn to consume commercial fish feed.
Life History: Bluegill spawn when water temperature reaches 70 degrees F. usually May through early September. Spawning peaks in May and June. Males construct nests by fanning
actions of the tail in 1 - 4 feet of water, preferring sand or gravel bars near shore. However, they will build nests in any possible substrate. Nests are 1-2 feet in diameter and 2-6 inches deep. Males clean and guard eggs and protect newly hatched fry. Bluegill are prolific spawners averaging 18,000 eggs per spawn. Their fecundity makes them an excellent forage species to stock as prey for largemouth bass and other carnivorous fish.
Bluegill are highly suitable for ponds and commonly stocked in combination with largemouth bass. Prolific bluegill reproduction provides a self perpetuating forage base able to support a bass population that includes large individuals of interest to anglers.
Oklahoma state record bluegill sunfish: 2 lb 6oz.
Lepomis cyanellus - green sunfish
Identification: Green sunfish are usually olive green colored on dorsal and sides. The ventral portion of the body is yellow. Green sunfish do not have the vertical barring found on the bluegill. Characteristically, the green sunfish have a series of dendritic turquoise lines under the eyes. Green sunfish are known by many names. Some of the most common are: perch, goggle eye, black perch and rice slicks.
Habitat: Green sunfish are a hearty species found almost everywhere. They tolerate poor water quality and may be, along with bullhead catfish, the only surviving species in the ephemeral pools of small streams and shallow ponds. They prefer creeks and ponds with muddy bottoms. Green sunfish are territorial. They prefer the cover of rocks, weeds roots or eroded stream banks.
Natural Diet: Green sunfish feed on a variety of insects , insect larvae, snails, crayfish and small fish. The mouth of the green sunfish is larger than that of the bluegill and it can swallow fish almost half the size of its own body. They will also learn to consume commercial fish feed.
Life History: Reproduction occurs May through early September but predominantly from late May to early July. Nesting habits are similar to the bluegill. Males build the nest with a fanning action of the tail. There may be many nests grouped together. Green sunfish are prolific spawners and often overpopulate and become stunted in ponds with few or no bass. Sexual maturity is reached by the end of the second year. Green sunfish compete with largemouth bass for food and will eat smaller fish and minnows. Small populations of green sunfish do not appear to affect bass populations or upset pond balance. Green sunfish are known to naturally hybridize with several other sunfish species.
Oklahoma state record green sunfish: 2 lb 7oz.
Hybrid bluegill X green sunfish
This hybrid is the result of crossing a male bluegill with a female green sunfish. It combines physical traits and habits of both species. The fish exhibits hybrid vigor in an increased growth rate and aggressive feeding behavior. Hybrid bluegill can reach a weight of 3/4 to 1 lb. in 3 years. They readily consume commercial pelleted fish feeds and are caught on hook and line at a rapid rate. About 70-90 percent of hybrid bluegill are male. The fish must be restocked periodically to maintain populations. (See LU fact sheet "Home Food Fish Production" for details on pond culture of this fish.)
Oklahoma state record hybrid bluegill: 1 lb. 14 oz.
Lepomis megalotis - longear sunfish
Identification: The longear sunfish gets its name from the elongated opercular flap on the upper edge of the gill cover. Maximum size is usually 5 inches. Longear sunfish are olive to turquoise green in color. Males have variegated iridescent green or orange pigment. No orange spots. Opercular flap is iridescent green with a thin white border.
Habitat: These sunfish are frequently found in clear, rocky, hard bottomed streams with a permanent flow and numerous pools. They inhabit shallow weed beds and avoid strong currents.
Natural Diet: Longear sunfish feed predominantly on small insects and insect larvae but occasionally feed on small fish and other aquatic organisms..
Life History: Spawning is from early May to late July. Males build and guard nests located on gravel bars in shallow water. Nesting behavior is similar to other sunfish species. Usually not found in ponds unless the pond is located near a stream that forms some connection with the pond during heavy rains.
Lepomis humilis - orange-spotted sunfish
Identification: The orange-spotted sunfish is a small, usually less than 4 inches in length. It is a brilliantly colored sunfish. The dorsal region of the fish is olivaceous to silvery green depending on water clarity. Bright orange spots on the side of the fish give it its name. Males in breeding condition are particularly colorful, with violet vertical banding in the dorsal and upper lateral regions and bright orange breast and belly.
Habitat: Orange-spotted sunfish are common inhabitants of streams but not so prevalent in ponds and lakes. They can tolerate high turbidity and show little decided preference for bottom type.
Natural Diet: Predominantly feeds on aquatic insects and insect larvae.
Life History: Nesting behavior is similar to other sunfish species. Males build and defend nests in 4-24 inches of water. Preferred nesting substrate is sand or fine gravel. The spawning season is extended and begins when water temperature warms to 75 degrees in early spring. Spawning continues until water temperature exceeds 89 degrees F. Spawning peaks in May and June. Orange spotted sunfish populations can grow large in ponds with few or no largemouth bass. Large populations have become established in commercial catfish ponds.
Lepomis microlophus - redear sunfish
Identification: Redear sunfish are deep bodied, olivaceous to light green colored sunfish. Usually darker in the dorsal region shading to almost white on the belly. The eye is often reddish to orange in color. The fish is easily identified by the red to orange trim around the "ear flap" of the operculum.
Habitat: Redear sunfish prefer to live near the bottom of ponds, lakes and sluggish streams or pools adjacent to abundant aquatic vegetation.
Natural Diet: Also called the "shell cracker", the redear sunfish feeds heavily on snails and is used to reduce snail populations in ponds. Snails are intermediate hosts of yellow and black grubs often found under the skin and in the flesh of fish. By consuming snails, redear sunfish help reduce grub infestations. It will also eat aquatic insect larvae, small fish, cladocerans and other zooplankton species.
Life History: Redear sunfish nest in deeper water than most other sunfish species. Spawning beds are usually located in 4-6 feet of water. Nests are constructed in silt or gravel. Nesting behavior is similar to other sunfish species. Spawning occurs throughout the warm season months with two spawning peaks during the year. Sexual maturity is reached by the end of the second year. Redear are relatively large sunfish. They can attain a length of 12 inches and weigh as much as 2 pounds. Redear sunfish can be stocked in place of bluegill or in combinations that equal the total recommended bluegill stocking rate.
Oklahoma state record redear sunfish: 2 lb. 1 oz.
The black basses
Micropterus salmoides - largemouth bass
Identification: The largemouth bass, also known as black bass, is the largest species in the sunfish family. Record weight exceeds 20 lb. It is distinguished from other black basses by the upper jaw which extends beyond the posterior edge of the eye. Largemouth bass are dark green in coloration dorsally, fading to white on the belly. A dark stripe extends latterly along the side of the fish and is most prominent in the young. Species found in turbid water have much lighter coloration than those inhabiting clear water.
Habitat: Largemouth bass are abundant in most ponds and reservoirs. It also inhabits pools and eddies of many streams. They prefer shallow, weedy areas with plenty of cover. This popular sportfish is used extensively for pond stocking.
Natural Diet: As it’s name implies, the largemouth bass has an extremely large mouth capable of ingesting frogs, fish and even baby ducks. Crayfish, fish and insects often make up a substantial portion of the diet. Gizzard shad are important forage fish for largemouth bass in many reservoirs.
Life History: Spawning begins when water temperature reaches 62-65 degrees, usually in April or May. The male builds a nest about 2 ft. in diameter with a depth of 6 in. The nests are constructed near shore in water up to 4 ft. deep. Females can produce up to 7000 eggs per lb of body weight. Males fan eggs to keep them free of silt and guard the nest during the 5-10 day incubation period. Largemouth bass can reach a length of 12 inches in the third year.
Florida strain and Florida strain x northern strain hybrid largemouth bass are often stocked into ponds. Florida strain largemouth bass grow somewhat larger than Oklahoma native northern strains but take a hook less readily; also Florida strain bass are less cold tolerant and may die during severe winters, particularly in the northern part of the state. The Florida x northern hybrid strains can better tolerate cold and consequently have a higher survival rate in Oklahoma, although growth rate is reduced compared to pure Florida strains.
Oklahoma state record largemouth bass: 14 lb. 11.5 oz.
Pomoxis nigromaculatus - black crappie
Pomoxis annularis - white crappie
Identification: Black and white crappie are very similar species. They are identified by difference in number of dorsal spines. The black crappie has 7 or 8 dorsal spines, the white crappie has 5 or 6 spines in the dorsal fin. The crappie are dark greenish and silver dorsally shading to white on the belly. Black blotches and spots are randomly scattered along the sides of the fish. The white crappie has spots and blotches arranged in somewhat vertical bars. White crappie are the most common of the two species. Coloration depends on water turbidity. Crappie are pale in turbid water but become increasingly dark as water clarity increases.
Habitat: Crappie are found in the pools of streams and rivers but have adapted particularly well to reservoirs where they can be found in schools near brush piles and flooded timber. They are tolerant of turbid water. Crappie are not well suited to ponds smaller than about 100 acres. Crappie compete with largemouth bass for food. They often over overpopulate small ponds resulting in thousands of stunted crappie and poor angling. Black crappie are somewhat more suited for pond stocking but only marginally so. Crappie reproduction may be controlled by maintaining a large population of largemouth bass in the pond.
Natural Diet: Young crappie feed on zooplankton and other microinvertebrates and small crustaceans. Adults prefer small fish.
Life History: Spawning occurs in the spring when water temperature reaches 60 - 65 degrees F. Spawning habits are similar to other sunfish, however, nests are usually found in sand or gravel in 6 - 12 feet of water. Crappie are prolific spawners. Females can deposit 3000 - 15000 eggs.
Oklahoma state record white crappie: 2 lb. 1 oz.
Family: Ictaluridae, The Catfish
Catfish are a commercially important food fish. The channel catfish is cultured throughout the much of the U. S. Although most are raised in along the Mississippi river in Mississippi and Arkansas.
Ictalurus punctatus - channel catfish
Identification: Bluish-gray to greenish - yellow shading to white underneath. Young channel catfish have a few black spots on the sides of the body. The tail is deeply forked. The rounded anal fin helps distinguish the channel catfish from the blue catfish with its straight edged anal fin. Channel catfish rarely exceed 50 lb. while the blue catfish can weigh as much as 150 pounds.
Habitat: Channel catfish are stream dwellers and found in many large rivers and their tributaries in North America. They have also adapted well to ponds and reservoirs. The channel catfish is a commonly stocked fish in ponds and is now an important aquaculture species in the United States. The channel catfish is typically bottom dwelling and seeks cover in undercut banks rock crevices and logs.
Natural Diet: Channel catfish are omnivorous and will eat both living and dead food items. Channel catfish feed by touch, taste and sight. Their barbels or "whiskers" are sensitive and well adapted to finding food in turbid water. A large part of their diet consists of insects and larvae but channel catfish will consume, crustaceans, snails, fruits vegetable matter and other fish. Catfish readily accept commercial fish food and can reach weights of 1 lb or more the first year stocked.
Life History: Spawning begins when water temperature reaches 75 degrees F. Channel catfish are cavity spawners and will deposit eggs in hollow logs, undercut banks and muskrat or beaver runs. Artificial spawning cavities can be created with milk cans, plastic buckets or similar materials. Catfish usually do not spawn in ponds unless artificial spawning containers are present in the pond. Males guard nests after spawning and fan eggs with their tails to provide aeration and keep eggs clean. Egg incubation period lasts 6-10 days depending on water temperature. Maturity is reached when the fish are 13-16 inches long, usually in the third or fourth year.
Oklahoma state record channel catfish: 30 lb. 0 oz.
Ictalurus furcatus - blue catfish
Identification: The catfish and the channel catfish are often confused, however, the blue catfish is distinguished by a straight - edged anal fin and steel blue color. The tail is deeply forked. The back slopes in a steep straight line from the dorsal fin to the snout. Blue catfish become quite large and can weigh up to 150 pounds.
Habitat: The blue catfish inhabits large rivers and is rarely found in tributaries or small streams. Blue catfish can be stocked successfully into ponds. Stocking rates are the same as for channel catfish.
Natural Diet: Blue catfish are omnivorous and eat a wide range of natural foods living and dead. Predominant food organisms are insects, insect larvae, fish, worms, mussels, crayfish and frogs. Blue catfish readily accept commercial fish food and grow well.
Life History: Spawning begins in late spring when water temperature reaches 70-75 degrees F. Blue catfish are cavity spawners like the channel catfish and exhibit similar nesting behaviors. Blue catfish will not spawn in ponds unless artificial spawning cans are placed in the pond. These fish are highly mobile and move as much as 90 miles down river in 1 week.
Oklahoma state record blue catfish: 85 lb. 4 oz.
Ameiurus melas - black bullhead
Identification: Black bullhead are usually small, less than 2 lb., black to olive colored dorsally, shading to white or yellow. Bullhead collected in turbid water usually have lighter dorsal coloration and yellow bellies. Barbels are black or dark gray. The tail is not forked like the channel catfish or blue catfish. It is almost squared off and slightly notched.
Habitat: This is a common and widely distributed species in ponds, lakes and sloughs, however, the black bullhead is rarely found in flowing waters. Black bullhead are tolerant of high temperatures, low dissolved oxygen levels and many pollutants. It and the green sunfish may be the only fish species found in many small shallow ponds and pools. Black bullhead are characteristically found in soft bottomed ponds with high turbidity.
Natural Diet: Like other Ictalurid catfish, the black bullhead is omnivorous. Midge, mayfly and other insect larvae make up a great portion of the diet. It will also eat crayfish, plants, worms, mollusks and minnows. Bullheads will consume commercial fish food. Like most catfish species, black bullhead most actively feed from dusk to dawn.
Life History: Spawning occurs in late May and June. Eggs are laid in a mass under vegetation or debris. Black bullhead spawn prolifically and without adequate predation, overpopulate and become stunted in small ponds. Young black bullhead form schools that appear conspicuously in the water as moving black "balls". A male guards the school of young fish for about 2 weeks after hatching. Schools disperse as fish reach about 1 inch in length.
Thomas Jefferson, in his diaries, recorded that he stocked bullhead catfish, chub and carp into his fish pond at Monticello.
Oklahoma state record black bullhead catfish: 6 lb. 13 oz.
Pylodictis olivaris - flathead catfish
Identification: The flathead catfish has a distinctively large, broad head and square tail. The body is flattened somewhat and has a brownish mottled appearance. The belly is yellowish - white. This is a large species that can attain a weight of 100 lb.
Habitat: Flathead catfish are a solitary species found in many reservoirs, often in the deep water and "rip rap" rocks of the dam. They live in deep holes of river beds and are attracted to caves crevices and other cover. The flathead is sedentary and secretive. It lurks under cover, darting out only to engulf smaller fish swimming nearby. Flathead catfish are also known to forage widely at night.
Natural Diet: The young flathead subsist on an omnivorous diet; as they grow and mature, the diet becomes almost exclusively piscivorus. Do not stock flathead catfish into ponds. They will eventually consume most other fish in the pond.
Natural History: Spawning occurs in June and July. Mature flathead are about 18 inches in size. They are cavity spawners and their spawning habits resemble those of the channel catfish. Young flathead form schools that disperse by the end of the growing season as the young fish mature. Juveniles are found undercover and in the debris of shallow water or pools. Adults live almost exclusively in deep pools.
Oklahoma state record flathead catfish: 71 lb.
Family: Percichthyidae, The temperate basses
Hybrid striped bass
Striped bass and white bass are important food fish in the U.S. Most striped bass used for food are produced in aquaculture ponds. White bass, also called sand bass, are popular sportfish in reservoirs and in rivers during the early spring spawning period.
Identification: The temperate basses are identified by having tow dorsal fins, the first with 9 spines the second with 1 spine. There is a small spine at at about the mid-point of the opercle. Hybrids of white bass X striped bass are now produced for pond stocking by a few commercial fish hatcheries. They can be identified by broken longitudinal lines on the sides of the fish.
Hybrid striped bass biology: Hybrid striped bass eat a diet consisting mostly of fish. They tend to form schools when stocked in numbers in lakes or ponds often feeding on schools of shad near the water surface.
Hybrid striped bass grow well on fish feed and adapt well to ponds. They are aggressive sportfish and provide good tasting table fare. Although they provide an interesting addition to the sportfish pond, hybrid striped bass do not reproduce in ponds and they tend to go into shock and often die when caught on hook and line. This fish requires active pond owner management and regular feeding to perform well.
Like the striped bass, the hybrid striped bass has sharp opercle flaps that can easily cause cuts if carelessly handled.
Oklahoma state record hybrid striped bass: 23 lb. 4 oz.
Family: Sciaenidae, The Drum
Drum receive their name from the sound these fish make during spawning season. It is most likely caused by abdominal muscles vibrating against the swim bladder and may be a means of communication during spawning season. These sounds are produced only in the daytime and usually in the afternoon. Otoliths, or small ear bones of this fish have been found among native American artifacts and may have been used as medicinal or good luck charms. THe drum are considered good food fish.
Aplodinotus grunniens - freshwater drum
Identification: The drum is high backed, and laterally compressed. Color shades from gray on back to silvery sides and white underneath. The snout is blunt and the mouth is near horizontal. Caudal fin is rounded. The drum has 2 distinct dorsal fins.
Habitat: Drum are found in clear watered rivers and reservoirs with rocky shorelines. Growth is often best in small reservoirs.
Natural Diet: The drum is a bottom feeding fish. Food items consist of snails, mussels, crayfish, aquatic insects and minnows found among rocks and the substrate. Freshwater drum may help control snails and consequently, black and yellow grub infestations when stocked in ponds.
Natural History: The drum spawns in April and May Depositing floating eggs over gravel bars and along sandy shorelines or in open water. Nests are not constructed and no parental care is given to young.
Oklahoma state record freshwater drum: 38 lb.
Family: Clupeidae, The Herring and Shad
The Clupeidae contain the gizzard and thread fin shad which are some of the most important forage fish . These species provide the food needed to maintain largemouth bass, white bass and striped bass populations at relatively high levels in reservoirs throughout the U.S.
Dorosoma cepedianum - gizzard shad
Identification: Gizzard shad are often found in large schools in the pelagic waters of reservoirs, although a few can be found along shorelines. The fish can be identified by the elongated last ray of the dorsal fin. This ray is similar to that of the threadfin shad except the threadfin has a much more tenuous final ray and tends to be of a yellowish-silver coloration. Gizzard shad are silvery colored fish with a blue spot behind the gill cover. Shad are more slimy than most other fish and tend to go into shock and die easily. Maximum weight is about 3 lb.
Habitat: Gizzard shad are most at home in the pelagic or open water of large reservoirs or large streams. They are often observed in large shoals near the water surface and prefer deep calm water.
Natural Diet: Young gizzard shad feed mainly on plankton. The fish is a filter feeder and strains phytoplankton and zooplankton from the water column through its gill rakers. Mature gizzard shad tend to feed on the bottom, straining organisms from the mud.
Natural History: Gizzard shad gather in large groups to spawn in early spring, April to May. Eggs are scattered pelagically. No parental care is provided.
Some pond managers have successfully used threadfin shad as supplemental forage in trophy largemouth bass ponds in Texas and other southern states. Threadfin shad are not cold tolerant and will die when stocked in Oklahoma ponds. There use is not recommended.
Gizzard shad, although cold tolerant, are an even worse choice for pond stocking. They reproduce rapidly and are readily prone to overpopulation in ponds. Gizzard shad soon become too large to be consumed by largemouth bass or other predators.
Family: Cyprinidae - Minnows
There are hundreds of minnow species and they are found in most aquatic environments. Minnows make up a large part of the diet of many carnivorous species of fish and are often stocked in ponds as a supplemental food source for largemouth bass and channel catfish. Fathead minnows and golden shiners are the species most commonly sold for bait and supplemental pond stocking.
Pimphales promelas - fathead minnow
Identification: Fathead minnows are blunt-nosed fish 2-3 inches in length. Coloration is usually silvery gray to olivaceous brown with a dark lateral stripe. Males have three rows of tubercles across the snout.
Habitat: Usually found in small turbid streams and pools with mud or firm clay bottoms. The fathead is a pioneer species that can be found in intermittent streams and drainages after rains. Fathead minnows are highly tolerant of pollution, high salinity and low dissolved oxygen.
Natural Diet: Fathead minnows are omnivorous and opportunistic, eating what ever plant, animal material and detritis that is available. They will also consume commercial fish rations.
Natural History: Fathead minnows spawn repeatedly throughout the spring and summer. Eggs are usually attached to the underside of submerged rocks, logs, plants and undercut stream banks. Young hatched in early spring can reach sexual maturity and spawn by late summer. Fathead minnows can be stocked as a supplemental forage fish to enhance sportfish production.
Notemigonus crysoleucas - golden shiner
Identification: Golden shiners are the most popular bait minnow, attaining a length of up to 10 inches. Dorsally, coloration is olive-green shading into silver or brass on the sides and underneath. The lateral line is decurved and complete. A sharp keel is located between the pelvic fins and anus.
Habitat: Golden shiners prefer deep pools in streams, ponds and lakes with low turbidity and lush aquatic plant growth at the margins.
Natural Diet: Natural food items include: plankton, algae, rotifers and small crustaceans. They will also consume commercial fish rations.
Natural History: Spawning occurs in late spring and summer. Adhesive eggs are released in weed beds where they adhere to leaves and stems. There is no parental care of eggs or young.
Cyprinus carpio - common carp
Identification: Carp are identified by a sucker shaped mouth with two pair of yellow barbels on the upper jaw. Color is yellow to brassy on the sides, shading to white underneath. The first dorsal spine is large and serrated. The carp is the largest of the minnow species and is native to Asia. It was brought to Europe centuries ago and was introduced into the U.S. in 1870 - 1880.
Some genetic mutants have only a few large scales and are called "mirror carp", or have no scales and are called "leather carp". "Koi carp" are valuable, colorful ornamental varieties bred commercially and sold to hobbyists.
Habitat: Carp prefer warm waters but can be found nearly everywhere from small streams to large lakes. They are hardy fish, tolerant of pollution.
Natural Diet: Carp are omnivorous bottom feeding fish that eat plant and animal material. They prefer tender roots and shoots of aquatic plants and will root up large areas of mud to obtain this food. This feeding activity stirs bottom muds and greatly increases turbidity where the fish are active. Do not stock common carp into ponds. There feeding activity increases turbidity and lowers natural production of more desirable species.
Natural History: Spawning begins in early spring and continues through mid-summer. Reproductive activity coincides with rises in water level. Carp move into shallow water and females scatter large numbers of eggs over vegetation and debris. No parental care is provided.
Oklahoma state record common carp: 35 lb.
Ctenopharyngodon idella - grass carp
Identification: Grass carp, also known as white amur, are the largest fish in the minnow family, commonly attaining weights in excess of 30 lb in ponds. They have been known to exceed 80 lb in their native habitat. Grass carp are silvery to yellow-olive in color. They do not have the yellow-orange hue found in common carp. Scales are large. The head has no scales and is often darker than the body of the fish. There are three simple and seven branched rays on the dorsal fin. Grass carp, unlike the common carp, have no barbels. The tail is forked and the mouth is located terminally, at the tip of the head.
Habitat: Grass carp are native to the large, free flowing river systems of Asia. They were brought to the United States in the 1960's for use as a control for aquatic vegetation and as a food fish. Grass carp can be found in densely vegetated areas of soft, rooted aquatic plants.
Natural Diet: Grass carp are herbivores and prefer to feed on soft, rooted aquatic vegetation. They will also eat duckweed and other floating plants. They do not eat cattails and other, tough, emergent aquatic plants. Grass carp can eat their body weight in aquatic vegetation daily, making them very efficient for use in aquatic plant control. (See LU fact sheet " Controlling Aquatic Vegetation With Grass Carp".) Grass carp will also learn to eat commercial fish feeds.
Natural History: Grass carp require large river systems to successfully reproduce. Eggs are deposited and fertilized in rivers as water temperature approaches 60 degrees F. River current must be sufficient to suspend eggs above the river bottom for the 20-40 hour incubation period. They have been able to reproduce successfully in the Mississippi river and a large reproducing population exists in the lower Trinity river in south Texas.
Grass carp are difficult for the angler to catch. Most success is with dough balls made of white bread, spinach and corn. When caught, they make excellent table fare. The flesh is mild tasting, light, and flaky.
Oklahoma state record grass carp: 64 lb. 6 oz.
Family: Catostomidae, The Suckers
Ictiobus cyprinellus - bigmouth buffalofish
Identification: Bigmouth buffalo are large carp-like fish, dark blueish-green in color shading to white underneath. Lips are thinner than other buffalo species. Ventral fins of this species are nearly black.
Habitat: Bigmouth buffalo prefer the calm water large rivers and lakes. They can also be found in oxbows and river tributaries. The bigmouth buffalo is more tolerant of turbidity than other buffalo species.
Natural Diet: Diet of the bigmouth buffalo is largely made of zooplankton, copepodes cladocerans and amphipods.
Natural History: Bigmouth buffalo spawn in spring with rises in water level in streams when water temperature reaches 60-65 F. Eggs are deposited in shallow water over plants and debris. No nest site preparation or parental care is provided.
Bigmouth buffalo have demonstrated potential for use as a cultured food fish species.
Oklahoma state record bigmouth buffalo: 59 lb. 15 oz.
Family: Salmonidae, The Trouts
Trout are native to cold mountain streams with swiftly flowing water and high oxygen levels. Although carnivorous, most trout, particularly rainbow trout (Salmo gairdneri) are hatchery raised and accustomed to a pelleted fish food ration.
Trout are cold water fish and begin to die at water temperatures above 70 degrees F. and oxygen levels below about 5 mg/l.
Onchorynchus mykiss - rainbow trout
Identification: Brownish-green to black dorsally, shading through silver to white underneath. Dark colored spots cover the body. Mature fish have a wide pink band along the side of the body.
Habitat: Preferred habitat of rainbow trout is the cool, well oxygenated clear waters of mountain lakes and streams.
Natural Diet: Rainbow trout live on a diet of aquatic insects, crustaceans, mollusks and small fish. Trout readily accept commercial fish rations.
Natural History: Spawning normally occurs at water temperatures of 40-45 degrees F. in late February to early April. Egg incubation requires 50 days. Most trout are spawned artificially in the many trout hatcheries in the U.S.
Oklahoma state record rainbow trout: 10 lb. 4 oz.
Family: Cichlidae, The Cichlids
Oriochromis niloticus - nile tilapia
Identification: Nile tilapia are identified by a caudal fin with black vertical barring. The lateral line, extending along the sides is broken into two parts. The dorsal fin is spined and marked with black bars. Coloration is gray to silver with black mottling or barring on the sides.
Habitat: Native to rivers and lakes of central Africa. Tilapia are the most cultured food fish in the world. Their popularity has spread the species around the world. Tilapia can tolerate very poor water quality conditions and withstand dissolved oxygen levels near 0 mg/l.
Natural Diet: Tilapia are omnivorous, feeding on a wide variety of food items including leaves, algae, and other plant matter. Many species are filter feeders that strain plankton from the water. Tilapia readily consume and thrive on commercial fish rations.
Natural History: Spawning occurs repeatedly while temperatures remain above 76 degrees F. Male tilapia build a nest about 1 foot in diameter and 4 inches deep. Females deposit eggs in the nest which are fertilized by the male. The females carry the fertilized eggs in the mouth until they hatch. Young are guarded by the female for 2-3 weeks after hatching. When threatened, young swim in to the mouth of the female and remain there until danger has past. Reproductive success is very high.
Tilapia have been stocked with some success into trophy largemouth bass ponds as a supplemental source of forage during summer. They reproduce prolifically and provide much food for the bass. Tilapia are tropical fish and can not tolerate water temperatures below 50 degrees F. They begin to die in mid-November from the cold. Channel catfish will consume large amounts of these fish at this time. Tilapia must be restocked each spring in late April or May.
Tilapia have been cultured in Oklahoma as a food fish in cages, raceways and open ponds.
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• Agricultural Research and Extension Programs