28 Freshwater Fish Species in California (ID + Pictures)

California Freshwater Fish Species

1) Chinook salmon (Oncorhynchus tshawytscha)

The largest of North America’s Pacific salmon species, this economically important fish is commonly known as king salmon, blackmouth, Quinnat salmon, and Chinook salmon. It is an anadromous species that navigates upriver from the coastal areas of the Northern Pacific to spawn. This stunning fish is highly-prized by anglers as a sport fish and is well-loved throughout its range for its tasty, nutritious meat.

In California, Chinook salmon populations are declining due to the loss of habitat, poor coastal conditions, and overfishing. Historically, this species has been shown to be native to the Guadalupe River, which stems from the Santa Clara Valley and empties into the San Francisco Bay. Several Californian populations are now considered threatened or endangered.

2) Striped bass (Morone saxatilis)

Another anadromous fish, this perciform is now present in many inland regions throughout the US. It is considered a highly valuable species in recreational areas as it is extremely popular with anglers. It has also been introduced into several North American freshwater systems as a biocontrol measure for gizzard shad. The most successful breeding stocks are located closer to the Atlantic coastline of the US.

There were once no striped bass populations found in California, but they are now readily found in the Sacramento-San Joaquin Delta. They were introduced into the state as early as 1879. Just a year after, one was finally caught in Monterey Bay.

3) California golden trout (Oncorhynchus mykiss aguabonita)

Named for their brilliant golden coloration, this species is California’s very own freshwater state fish. Its designation as a fully independent species has been quite controversial, though many reliable data portals on fish species now recognize its independence. Some taxonomists refer to it as O. aguabonita. Its species epithet is derived from the body of water where it was first collected, Agua Bonita Falls in Volcano Creek.

The California golden trout has an unforgettable and unmistakable appearance. Its golden flanks are marked by deep red horizontal bands and up to 10 vertical, dark bands. Most of the fins have a fine white streak on their leading edges. These fish typically grow to a full length of about 12 inches (30 cm) in their native range.

4) Channel catfish (Ictalurus punctatus)

Known for their remarkable hardiness, channel catfish are among the most highly sought-after Ictalurids in the US. They can survive a wide range of conditions, including those in industrially polluted waters. Their presence in freshwater systems is most apparent throughout the east coast to Midwestern regions of the US, but California has its own robust populations as well. Major lakes tend to have the largest individuals.

The Californian state record for channel catfish is 53 lbs 8 oz (24 kg). It just so happens that this is the world record as well! This fish can grow to a remarkably hefty weight and is best caught in spring or fall, when ambient conditions are mild. Anglers are advised to search for them in areas where their natural prey choices, such as baitfish and crawfish, tend to lurk.

5) Largemouth bass (Micropterus salmoides)

An absolute angler favorite throughout its native range, the largemouth bass has a reputation for being an aggressive predatory species. Its large mouth and strong jaws are definitely hard to forget. It is known for being a fearsome fighter that resists the pull of anglers even as it is being hauled onto shore or a boat. The largest individuals are usually released once they are caught, especially as they are likely to be breeders.

Largemouth bass was introduced into California’s wetlands in 1891. The first populations were eventually formed by specimens that were obtained from Quincy, Illinois. These fish began reproducing in the Lake Cuyamaca waters of San Diego. More fish were subsequently introduced in later years. Today, populations that are known for massive individuals are found all throughout the state. 

6) White sturgeon (Acipenser transmontanus)

Known for growing to shocking lengths, this freshwater “monster” fish is often feared due to its resemblance to sharks. In truth, it is a gentle, toothless giant that prefers to remain on the benthos of lakes and river systems. It is now often cultivated in aquaculture farms for two main reasons: to meet the demands of the aquarium industry and for the production of its top-quality caviar. Harvesting species from the wild is illegal, but poaching continues to persist as sturgeon caviar sells for remarkably high rates.

Considered the largest freshwater fish species in North America, a single white sturgeon can weigh as much as 1,500 pounds! Its natural range extends through California and upwards into British Columbia. Though this fish can live for a century, it takes several years to become sexually mature and seems capable of growing in size for the rest of its life. Populations that are located in the Columbia River are considered the most productive of their kind.

7) Coho salmon (Oncorhynchus kisutch)

The coho or silver salmon has colors that change throughout its anadromous life cycle. As males occupy oceanic and coastal areas prior to spawning, they have distinctly dark-blue to silver coloration. They gradually lighten as they reach sexual maturity and their bellies may become light red to pink. Even their physical structure changes, with their snouts becoming more hooked at full maturity.

In California, populations of this salmonid are considered either threatened or endangered throughout most of their natural range. They mostly occupy riverine systems that are associated with the central and northern coastline regions. Large adults tend to reach a maximum weight of 22 pounds (10 kg) in these areas. The state prohibits their retention and highlights the importance of proper salmon identification to prevent unnecessary mortalities.

8) Rainbow trout (Oncorhynchus mykiss)

Rainbow trout is considered one of the least threatened among Oncorhynchus species in California. This is due, in part, to its hardiness and tolerance for conditions in disturbed environments. They have an impressive range throughout the state, with populations found as far south as San Diego. Resident populations tend to occupy upstream sections of rivers with challenging barriers, such as waterfalls.

As indicated by its common name, this species is known for its iridescent coloration. Its streamlined body is also marked with black spots and a pink to red-toned horizontal band on each side. In California, the largest of its kind may reach an impressive weight of 26 pounds (12 kg). On average, these cold-water fish have a fork length of 14 – 25 inches (35 – 65 cm).

9) Bluegill (Lepomis macrochirus)

A member of the sunfish family, this species is known for being a highly nutritious forage fish. It favors calm freshwater systems with high structural diversity. As it moves around in small schools, it seeks shelter and protection from submerged vegetation, where its ambush predators may also lie in wait. Growing to an average weight of about 4.4 pounds (2 kg) in the wild, mature bluegill are distinguished by their blue-purple face coloration, dark vertical bands, and yellow-orange abdomens.

This ecologically important species plays a central role in the food chain of shallow lakes, ponds, streams, and reservoirs. They thrive best in warm water temperatures ranging from 27 – 32˚C (80 – 90˚F). They are readily found throughout California’s wetland systems, particularly at low elevations. In freshwater systems where predators are scarce, they have the tendency to become overpopulated.

10) Black crappie (Pomoxis nigromaculatus)

Another markedly important forage fish, the black crappie is known best for its laterally compressed body type and its distinct pattern of black spots. Its species epithet, nigromaculatus, is Latin for “black-spotted”. They may look quite similar to white crappies and are distinguished by the number of spines (7 – 8) of their dorsal fins.   

Black crappies usually grow to a maximum length of about 8 inches (20 cm), but a massive specimen was recently caught in Clear Lake, California. This fish had an impressive length of 17 ¾ inches (45 cm), now the state record for this species. With a preference for clear, calm water, black crappies are best found in pools with submerged vegetation.

11) Brown trout (Salmo trutta)

Brown trout was introduced into California’s freshwater systems in the late 1800s. Originally an anadromous species, it now has fully landlocked populations that spawn throughout rivers and lakes across the US. One of its morphs is commonly referred to as lake trout or Salmo lacustris. Though many populations in California, especially those in the Sierra Nevada, are capable of reproducing naturally, the state’s wildlife department may still occasionally stock fingerlings as a response to fishing pressures.

Californian anglers are fond of using flyfishing techniques to lure in this species. The best places to target them include Shasta Lake, Hat Creek, Twin Lakes, Lake Almanor, Crowley Lake, Baum Lake, and Hell Hole Reservoir. They may be challenging to catch, even in these freshwater systems, due to their shy and wary nature.

12) Brook trout (Salvelinus fontinalis)

In California, populations of this non-native trout species are largely concentrated in the wetland zones of the Sierra Nevada Mountains. Trophy sizes of the fish, which can grow to a full length of about 25 inches, can be caught in large lakes. At streams of higher elevations, mature individuals don’t grow as large.

The brook trout is known for its delectable meat. Some anglers consider its meat the tastiest among North American trout species. It can be prepared in all sorts of ways, but is best consumed fresh and in the great outdoors. Its nutritional value can be attributed to its diverse diet in the wild. Some of this fish’s favorite treats include protein-rich aquatic insects. Larger individuals may also feed on amphibians and aquatic mammals.

13) Redear sunfish (Lepomis microlophus)

Though this fish isn’t native to California’s waters, the world record was caught in a lake situated on the California/Arizona border. The impressive specimen weighed more than 5 pounds (2.3 kg). This is more than 5 times heavier than the average weight of mature redear sunfish, which is around just 0.99 pounds (0.45 kg)! Also referred to as Georgia bream, rouge ear sunfish, and perch, this popular sport fish now has populations all across the country.

In terms of appearance, the redear sunfish is remarkably similar to its close cousin, the bluegill. Key differences between the two species include coloration and average size. The redear is, of course, distinguished by the red-orange edge of its operculum. It is also usually larger than most bluegills in the wild. This gamefish is known for being quite feisty and is often spotted searching for shellfish, its favorite prey type.

14) Blue catfish (Ictalurus furcatus)

The largest of all Ictalurids in North America, the blue catfish can grow to spectacular lengths within its maximum lifespan of 20 years. A single fish can weigh as much as 150 pounds (68 kg), much like a full-grown human adult. Smaller-sized specimens are often misidentified as their close cousin, the channel catfish. The blue cat is distinguished by its dorsal hump and heavy, bluish-grey body. Its anal fin has 30 – 36 rays, unlike that of the channel catfish which has 29 rays at most.

The blue catfish populations of California are frequently found in the deeper recesses of considerably-sized rivers and reservoirs. They are highly tolerant of significant temperature changes throughout the year. They are also able to survive in moderately saline water, with their growth rates peaking at a mild salinity of 7 – 8 ppt. Anglers searching for this heavyweight champion are more likely to find them in the lakes of Southern California.

15) Arctic grayling (Thymallus arcticus)

This fascinating gamefish is known for being an elusive species that highly appeals to fly fishers. In California, it is found in just one fairly remote lake system in a high-altitude forest area. Lobdell Lake is a must-visit for sightings of the grayling and is a great location for those learning fly fishing techniques. Arctic graylings jump out of the water there, flashing the iridescent colors of their dorsal fins.

Count yourself lucky if you can inspect the sail-like dorsal fins of this species as they are a wonder to behold. Consisting of several soft rays, the fin is silvery and violet. Upon close inspection, you’ll find that it is delicately dotted with pale reddish speckles. At maturity, this fish typically reaches a maximum size of just 8 – 15 inches (20 – 38 cm). They can persist in cool waters where other species may struggle to survive as they have a notable tolerance for low oxygen levels.

16) Kokanee salmon (Oncorhynchus nerka)

The kokanee salmon is actually the landlocked counterpart of anadromous sockeye salmon, with which it shares the same scientific name. There is still debate as to whether the landlocked populations can genetically be considered a separate species or subspecies. Known for their striking red to orange coloration, these geographically isolated populations start out their lives as juveniles in streams. They then mature in larger lake systems, after which they return upstream to spawn.

California’s kokanee salmon are largely restricted to its northern wetland systems. Anglers may also find small populations in the central reaches of the state. Trophy-size fish can be caught in a handful of lakes, including Berryessa, New Melones, and Donner Lake.

17) Flathead catfish (Pylodictis olivaris)

The second-largest catfish in its native range, P. olivaris is also known as mudcat, goujon, Mississippi cat, and yellow cat. On average, this fish can grow to a mature length of 25 – 46 inches (63 – 116 cm). It must reach a considerable length prior to becoming sexually mature. By the time some individuals first spawn, they may even be 10 years old!

Considered a non-native in California, this species was unintentionally introduced into Diamond Valley Lake, from which a self-sustaining population eventually became established. Anglers searching for this particular species have higher chances of finding them in Southern California’s lakes. The state record for flathead catfish is an impressive 72-pounder (33 kg).

18) Cutthroat trout (Oncorhynchus clarkii)

Cutthroat trout has four main geographical groups in the US. Those in California are considered “coastal cutthroat trout” and belong to the type subspecies O. c. clarkii. These fish may also be referred to as harvest trout or sea-run cutthroat trout. Their southernmost reaches extend into California’s northern waters, where they are present in small, fragmented populations. Anthropogenic activities such as logging and agriculture threaten their survival.

This species is often mistaken for rainbow trout due to their similar form and coloration. Compared to the latter, coastal cutthroats tend to have more spots and a more streamlined form. As their common name suggests, they are distinguished by bright red markings that look like slashes on their lower jaws. 

19) Smallmouth bass (Micropterus dolomieu)

Even more formidable than their popular black bass cousins, the smallmouth is an angler favorite that puts up a memorably tough fight. This game fish has populations that are spread out all over North America, in part due to illegal and accidental introductions. It plays an important role in the food chain of freshwater systems as it is an apex predator. This powerful swimmer can survive in cool water with strong currents.

Smallmouth bass fingerlings are now intentionally stocked in many recreational lake systems to meet annual fishing demands. This fish was introduced into the Napa River in the late 1800s, after which resulting populations remained largely restricted to the northern parts of the state. It favors rocky habitats, which are much scarcer in the waters of Southern California.

20) Common carp (Cyprinus carpio)

The remarkably hardy common carp is now found in so many regions outside of its native range. This invasive species is considered highly destructive as its growing populations can lay waste to entire freshwater ecosystems. Farmed as far back in history as the Roman civilization, this food fish thrives in temperate climates and can easily survive in both frozen or warm ponds and lakes.

In California, common carp populations are often found in eutrophic lake systems. They favor turbid waters with soft bottoms. Odds are anglers are likely to find this fish in most of the state’s major freshwater bodies.

21) California killifish (Fundulus parvipinnis)

The golden state’s very own killifish, F. parvipinnis is a tiny species that grows to a full length of just 11 cm (4 inches) at maturity. Its small body is relatively thick and is posteriorly marked by a square-shaped tail fin. Its yellow-green fins are very small and gradually darken as the breeding season approaches. The bellies of sexually mature individuals notably lighten to a yellowish hue.

Tolerant to a wide range of coastal to inland conditions, California killifish populations are largely concentrated in the estuaries and marshes of Baja in Southern California. They also occur through polluted coastal wetland systems, including the Tijuana River. Despite low oxygen, high turbidity, and brackish water conditions, these fish continue to persist by foraging for small snails and insects. 

22) Fathead minnow (Pimephales promelas)

The fathead minnow has a knack for surviving in freshwater bodies where many other fish species can’t. It is an omnivorous fish that feeds on a wide variety of small prey types, including those that live within bottom substrates. Its tolerance for harsh aquatic conditions has made it useful in toxicity studies, particularly those that involve endocrine disruptors in synthetic materials (e.g. resin, plastic).

Fathead minnows are not native to California, but they are now present in stable populations throughout the Sacramento watershed system. Their presence there has been associated with the decline of some native fish populations, such as those of the shortnose sucker (Chasmistes brevirostris) and Colorado pikeminnow (Ptychocheilus lucius).

23) Golden shiner (Notemigonus crysoleucas)

Known for its use as an effective baitfish, the golden shiner has been introduced into freshwater systems far beyond its native range. It is cultured all throughout the US and is found in practically all types of water bodies, big or small. It thrives best in calm, quiet waters as it is a visual feeder that favors areas with submerged vegetation or weeds. They can also filter feed within the water column itself.

In the late 1890s, the golden shiner was intentionally seeded in selected parts of California as a forage fish. It is now found all throughout the state, but its effect on native fish species has yet to be thoroughly investigated. Notably tolerant of freshwater pollution and low oxygen conditions, this small fish roams around in shoals.

24) Pink salmon (Oncorhynchus gorbuscha)

This species is known for being the smallest among salmonids of the Pacific. However, despite its size, it is the most abundant. It is now commercially harvested in the hundreds of thousands of tons per year in several key coastal areas throughout the Northern Pacific. Unfortunately, due to the massive increase in catchment rates of coastal populations, many are now in decline. Those in California’s waters have been classified as imperiled by NatureServe.

Salmon populations that make their way to California’s coastline and wetlands find themselves at the southernmost reaches of their Eastern Pacific range. Some of these may be self-sustaining, though it is likely that most will soon disappear from the state’s waters. This is due, in part, to their brief lifespans and the tendency for fry to enter oceanic waters soon after hatching.

25) Pacific lamprey (Entosphenus tridentatus)

The largest of all lamprey species in California’s waters, E. tridentatus has both landlocked and anadromous populations. Larvae usually begin their lives in inland streams and may remain there for up to 7 years. Their morphology drastically changes once they mature into considerable lengths of 14 cm (5.5 inches) or more. At this size, individuals make their way downstream to an estuarine or coastal location and begin to parasitize larger fish, such as salmon or flatfish.

Found in dozens of watershed areas throughout California and nearby states, Pacific lamprey are listed as a species of concern due to their declining abundance. Their presence is vital in many natural ecosystems as they play a key role in the food chain. The degradation of water quality due to anthropogenic disturbance is a major factor in the loss of local populations.

26) Delta smelt (Hypomesus transpacificus)

Labeled by National Geographic as the “icon of California water wars”, the delta smelt is in severe decline. Endemic to the California Delta, this small, short-lived species favors estuarine zones where considerable mixing between freshwater and saltwater occurs. Highly sensitive to environmental changes, it is considered an important bioindicator of ecosystem health.

In an effort to protect this tiny but important fish, state water projects have largely been limited or modified at the cost of ideal water provision to farmlands. Unfortunately, the delta smelt remains to be near-extinct. Man-made pollutants and the introduction of non-native species may have also been instrumental in its inability to recover.

27) Brown bullhead (Ameiurus nebulosus)

Known for its remarkable adaptability, it’s no surprise that this catfish can thrive in a wide variety of freshwater ecosystems with suboptimal conditions. With nary any natural predators, it can easily persist for long enough to reach considerably large sizes. Adults in the wild can measure anywhere from 8 – 20 inches (20 – 50 cm). They are opportunistic feeders with a preference for benthic fish, mollusks, aquatic insects, and plants.

The brown bullhead is considered a non-native species in California as its native populations hail from North America’s eastern wetlands. There are now self-sustaining populations across the entire stretch of the state. Introduced into western waters for food and sport, their presence as a predatory fish has been linked to the decline of some native prey fish.

28) White bass (Morone chrysops)

White bass are often mistaken for striped bass (M. saxatilis) due to their similar features, including horizontal stripes, and near-identical geographical distribution. The main differences lie in their body and mouth shape. White bass have a more rounded body structure and their mouths have a single tooth patch (vs the two tooth patches of striped bass). Unfortunately, the two species tend to hybridize to produce young that are even more difficult to distinguish from their parents.

M. chrysops was likely introduced into California as a game fish. Its populations are frequently found in calm lakes and large reservoirs. The upstream segments of warm, slow rivers are also an ideal habitat for this carnivorous species. They gather in shallower areas to spawn in spring.