Although Connecticut is the third smallest state in the US, it boasts a rich diversity of both wetland and marine resources. With inland freshwater systems and a fairly protected coastline, many of its developed areas have economies that are linked to the presence of water. In fact, the most populous region of the state is found in the valley through which the Connecticut River flows.
Connecticut’s major bodies of freshwater include considerably-sized lakes linked to river and stream systems with estuarine zones. Many of these arise from important rivers occurring further inland and traversing through multiple neighboring states. While some of these systems were once regarded as receptacles for all sorts of waste, the importance of their rehabilitation and conservation is now widely recognized.
If the state’s freshwater resources were never afforded the protection that they have today, large populations of dozens of important fish families would have been lost. As many river systems flow out into marine environments, the state has both anadromous and landlocked fish species, many of which are catchable and support local fisheries. Listed below are some of the most important species in Connecticut’s wetlands and reservoirs.
Connecticut Freshwater Fish Species
1) American eel (Anguilla rostrata)
The American eel is a catadromous species that matures and feeds in freshwater systems. When it is ready to spawn, it migrates to the Sargasso Sea and dies after releasing its gametes. Its juveniles and young adults return to freshwater habitats and remain there for about 10 – 20 years before migrating once more to spawn. Known for its dark and lengthy body, this eel is a food fish in Asia and Europe.
American eels usually drift into Connecticut’s rivers as “glass eels,” which is the common term for their larval form. When they encounter low barriers in their migration pathway, they are able to slither over short distances of terrestrial features. Nocturnal, they eventually find themselves in productive lake and river systems. As they grow into their mature form, they prefer to stay away from currents.
2) Atlantic sturgeon (Acipenser oxyrinchus)
The Atlantic sturgeon comes in two subspecies – A. oxyrinchus oxyrinchus and A. oxyrinchus desotoi. Once remarkably numerous in the waters of Connecticut, where its native populations would reproduce, it is now listed as a threatened fish. Back when it could replenish its local populations, adults would leave saltwater habitats and enter the Hudson River to spawn. Their young would remain in the river for up to 7 years before venturing to sea.
Atlantic sturgeons are known for their small mouths and pointed snouts. Those found inland tend to measure around 2 – 4 feet (0.6 – 1.2 meters) long. In contrast, adults at sea may measure as much as 14 feet (4 meters) long. A combination of anthropogenic disturbances, such as those resulting from the construction of dams and the consequences of overfishing, have caused significant declines in local populations.
3) American shad (Alosa sapidissima)
Another historically important anadromous species that was once abundant along the East Coast, the American shad is a nutritious food fish. At sea, shad become sexually mature on a diet of filter-fed organisms. Once they are ready to spawn, they enter rivers and are able to migrate over considerable distances toward inland locations. Those in Connecticut have been found hundreds of miles upstream.
Considered the official state fish of Connecticut, the American shad is the largest of all locally-found herring species. Its populations in the Connecticut River have shown favorable rates of recovery, allowing for the survival of local fisheries. Today, their spritely juveniles are a common sight during calm, summer evenings along the state’s major river systems.
4) Shortnose sturgeon (Acipenser brevirostrum)
Now an endangered species, the shortnose sturgeon is usually found in coastal rivers. Long-lived, this seemingly prehistoric fish ventures further inland to spawn. It rarely migrates into high-salinity locations to feed, though it will occasionally search for food along shorelines if its riverine habitats are compromised. This species usually forages on small fish, bivalves, and bristle worms along the benthos of rivers and estuaries.
One of the state’s native freshwater fish species, the shortnose sturgeon has a self-sustaining population in the Connecticut River. During cooler months of the year, it tends to stay in the northern parts of the river system. In summer, it may migrate southward into estuarine locations. Often mistaken for the Atlantic sturgeon, the shortnose has a wider mouth relative to the width of its head.
5) Brook trout (Salvelinus fontinalis)
In Connecticut, brook trout populations are naturally found in cool streams. They prefer small and clear freshwater bodies with a moderate to fast current. Warm temperatures coupled with poor water flow may compromise the health of mature brook trout, which spawn in stream beds. Females deposit their eggs into depressions that they themselves construct.
Self-sustaining populations of this species are usually found in headwaters where other types of trout, particularly non-native species, are absent. In streams occupied by other salmonids, their numbers are “enhanced” by stocking hatchery-grown brook trout. These rarely disrupt the survival of other freshwater fish as they are rapidly harvested.
6) Atlantic salmon (Salmo salar)
A commercially important salmonid, the Atlantic salmon spends most of its life in marine environments. Adults only enter freshwater habitats once they are ready to spawn. Though their spawning runs in the Connecticut River were once highly prolific, local numbers of sea-run fish have dwindled considerably over the last century. Fortunately, restoration efforts are beginning to support a small, self-sustaining population once more.
Sea-run Atlantic salmon found in freshwater systems have no interest in feeding. Adults that are able to survive the spawning run return to sea and remain there until they are ready to spawn once more. Their juveniles remain in rivers and streams for up to 2 years. Called “smolt,” these young fish subsist on a diet of invertebrates, small fish, and the eggs of other salmonids.
7) Rainbow trout (Oncorhynchus mykiss)
The rainbow trout is a non-native fish in Connecticut’s waters. It is deliberately stocked into some of the state’s major streams and lakes to meet the fishing demands of local anglers. Interestingly, some of this fish’s survivors have managed to sustain their own populations. These “wild” rainbow trout have so far only been found in Hubbard Brook, Hartland.
Rainbow trout favor clear, cool, and oxygen-rich streams, rivers, and lakes. Once temperatures rise toward the end of spring, they usually migrate upstream in search of faster currents. Strains that are introduced into the state’s waters rarely survive the warm, summer conditions. Impressively, however, the state record for this species was a 14-pound fish caught in a reservoir.
8) White sucker (Catostomus commersonii)
Named for its suction-feeding habit, the white sucker is distinguished by its fleshy lips, rounded body, and grey-green to brown coloration. It typically grows to about 20 inches (51 cm) long on a diverse diet of macroinvertebrates, small fish, plant matter, and algae. An important member of the freshwater food chain wherever it is found, it is naturally preyed upon by trout, bass, pike, and catfish.
The white sucker is generally abundant in most of Connecticut’s streams. From March to May, this fish is most likely to be found moving upwards in tributaries. When it is present in large numbers, its runs are a visual spectacle as hundreds of individuals may force themselves into the same pools. The sheer abundance of this species makes it one of the most biologically important native fishes in the state.
9) Creek chubsucker (Erimyzon oblongus)
Another member of the sucker family (Catostomidae), the creek chubsucker favors slow-moving bodies of freshwater. In Connecticut, it has a patchy distribution and is naturally found in streams, clear pools, and lakes. This species prefers to remain close to submerged vegetation, where it can forage along the benthos under the cover of leaves and shoots.
While adult creek chubsuckers tend to be solitary, preferring to search for prey on their own, their young often form significant parts of mixed schools with juvenile minnows. As this species tends to share spawning grounds and feeding areas with its cousin, the white sucker (C. commersonii), it must compete for food and resources. The increased siltation of streams can unfortunately compromise local populations and has evidently led to their decline.
10) Chain pickerel (Esox niger)
Set apart by the chain-like pattern on its flanks, the chain pickerel has a mixture of yellowish, greenish, brown, and black pigments. Able to grow to an impressive length of about 30 inches (76 cm), it is known for its pole-like shape and pointy head. Prior to reaching its full size, its pattern gradually changes. Juveniles may look quite different from their adult counterparts, though they retain a similar body shape.
The chain pickerel has a generous distribution in Connecticut. Stable populations are found in many of the state’s river and lake systems, but they are more abundant in streams that are east of the Connecticut River. Their distribution in western parts of the state is more irregular. Favoring shallow freshwater systems, this species is an ambush feeder and is partial to smaller fish and crayfish.
11) Redfin pickerel (Esox americanus americanus)
Closely related to the chain pickerel, the redfin pickerel is a valuable type of pike in Connecticut. Its distribution is largely restricted to the shallow backwaters of ponds and to streams with high visibility conditions. Though it may occasionally be found in rivers and lakes, it prefers to remain along vegetated shorelines, where it can search for prey and ambush them.
The smallest type of pike in the state, the redfin pickerel grows to a maximum length of just 15 inches (38 cm). In local freshwater bodies, specimens rarely grow to more than 9 inches (23 cm) long. This species is distinguished by dark, vertical bars extending over both sides of its elongated body. As indicated by its common name, its fins tend to have reddish coloration.
12) Burbot (Lota lota)
Though the burbot is occasionally found in Connecticut, its presence is attributed to a small and elusive population in the Housatonic drainage system. The state is the southernmost point of this freshwater cod’s distribution. With a preference for cold and deep water, the burbot favors lakes and rivers with ample bottom structure. Those found in cool streams spend their days hiding under rocks and under the cover of vegetation.
Morphologically, the burbot looks to have the shortened features of an eel and the slightly rounded head of a catfish. Its common name alludes to the presence of a singular barbel extending from its chin. Its nostrils have tubular projections. Unlike eels and catfish, this fish has two dorsal fins – the anterior one is short, whereas the posterior one extends further back and tapers close to its caudal region.
13) Brown bullhead (Ameiurus nebulosus)
Also known as “mud cat” and “horned pout”, the brown bullhead is a hefty member of the Ictaluridae family. Adults that are fished out of productive systems may measure as much as 21 inches (53 cm) long and weigh as heavy as 3.6 kg (7.9 pounds). Distinguished by their greenish-brown coloration, these fish may have a seemingly dirty appearance that helps them remain camouflaged on muddy bottoms.
In Connecticut, the brown bullhead is found in almost all slow-flowing bodies of freshwater. It is abundant wherever it is found, partly due to its tolerance of poor oxygen conditions, pollutants, and markedly warm temperatures. Nocturnal, it is somewhat underused as a target by local anglers. Those who go in search of it at night, however, should find that it eagerly takes baited worms.
14) Channel catfish (Ictalurus punctatus)
Though the channel catfish has the most widespread distribution of any Ictalurid in North America, it is a non-native freshwater fish in Connecticut. Not naturally found in the Atlantic coastal states further south of Maine, it has been widely introduced throughout the continent. Its populations are now stable components of the Connecticut River and its tributaries. Mature specimens may also be found in lakes and ponds.
Although the channel cat thrives best in large rivers and streams, it is fairly tolerant of poor conditions and high turbidity rates. This gives it a competitive edge against other native fish. Although it is a nocturnal species, it won’t hesitate to feed during the day. As a bottom feeder, it can expertly find prey with the use of its well-developed senses of smell and taste.
15) Pumpkinseed sunfish (Lepomis gibbosus)
A medium-sized member of the Centrarchidae family, the pumpkinseed sunfish is a prolific species. Outside of its native range, it has the tendency to compete with other small fish and become invasive. On average, it grows to about 4 inches (10 cm) long and rarely weighs more than a pound. Its size, coupled with its capacity to reproduce in a vigorous manner, gives it a key role in freshwater food webs.
Naturally found in most of Connecticut’s freshwater systems, it has an even distribution throughout the state. In large streams and lakes, pumpkinseed sunfish populations are quite abundant. Adults and juveniles are predominantly found in areas with vegetation. Though they are remarkably colorful, they have a knack for remaining camouflaged as the appearance of their skin looks like the reflection of sunlight on shallow beds.
16) Striped bass (Morone saxatilis)
A member of the Moronidae family of temperate basses, the striped bass is a valuable species due to its appeal to recreational fishers. This gamefish is also ecologically important as it can grow to impressively large sizes and helps control populations of smaller fish species via predation. The largest of its kind can measure up to 36 inches (91 cm) long and weigh as much as 126 pounds (57 kg)!
In Connecticut, striped bass are usually found throughout the Connecticut River and close to the rocky shores of estuaries. As they spawn or search for food, they may migrate further inland. Though some local populations remain in landlocked bodies of water through winter, those with access to coastal areas migrate further south as soon as temperatures cool.
17) White perch (Morone americana)
Despite its common name, the white perch is actually another type of temperate bass. Valuable as a sport and food fish, it is naturally found in tidal rivers and estuaries. In Connecticut, both native and introduced populations have been recorded in most major rivers and some landlocked ponds and lakes. This species tends to be abundant wherever it is found.
Though far from scarce, white perch can be quite undesirable for beginner anglers. Even predators may favor other types of fish over them because of the long, sharp spines on their fins. When their populations are left to freely increase in density, especially in enclosed bodies of water, they may begin to show signs of stunted growth.
18) Slimy sculpin (Cottus cognatus)
The slimy sculpin is a small, scaleless fish that favors cool bodies of freshwater in temperate zones. One of its most notable features is its relatively large and free pair of pelvic fins. These allow it to remain perched on bottom substrates and facilitate its “hopping” motion as it moves from place to place along the benthos.
Known for being extremely inefficient as a swimmer, the slimy sculpin lacks a swim bladder. As it usually remains under the cover of vegetation or detritus, rarely venturing far from shelter, it is best caught with a mesh net or seine. In Connecticut, entire populations tend to have a small spread, with some being restricted to a few square kilometers within a single stream.
19) Striped mullet (Mugil cephalus)
Though the striped mullet is more likely to be found in marine habitats, it occasionally ventures into freshwater systems. Able to tolerate a wide range of conditions, it can be found in bodies of water with depths of 0 – 120 meters. Those in Connecticut’s waters are usually restricted to estuaries and streams that are located close to the coast. The best time to search for local populations is in summer.
The striped mullet plays a valuable ecological role because it filter-feeds through a substance that many other fish are likely to avoid – the muck at the bottom of productive systems. It is also an important food fish. In some countries, this species is heavily fished and is grown in aquaculture setups to meet demand for its tasty meat and nutritious roe.
20) Yellow perch (Perca flavescens)
Known for its vivid yellow coloration and a set of dark vertical bars extending downward from its back, the yellow perch is an eye-catching fish. Due to its appearance, it may also be referred to as raccoon perch or striped perch. The fins of adult specimens may have reddish hues, which brighten as their spawning period approaches. Juveniles look like smaller versions of adults, but their colors may appear faded.
The yellow perch is quite abundant in Connecticut, with populations found in almost all major river and lake systems. In the state, it grows to a maximum size of about 15 inches (38 cm) long. Traveling in schools, this fish seeks shelter in areas with thick vegetation. Wherever it is found, it is an important food fish for waterfowl and larger sport fish species.
21) Tessellated darter (Etheostoma olmstedi)
A member of the Etheostomatinae subfamily of perches, the tessellated darter is named for its speckled appearance. Along its flanks are dark, irregularly-shaped blotches that look like the letter X. These blotches blend in with the brown skin of mature males, which become noticeably darker as they are about to spawn.
Although the tessellated darter is found in most of Connecticut’s streams, its abundance is quite inconsistent. In slow-moving streams, adults are usually found perched on the bottom. They subsist on a diet of aquatic insects and small crustaceans. With a preference for quieter bodies of water, they hide by burrowing into sandy or muddy substrates.
22) Alewife (Alosa pseudoharengus)
The alewife is a medium-sized type of herring with an anadromous life cycle. Its adults are found in oceanic habitats, feeding on zooplankton and traveling in schools. As the spawning period approaches, mature specimens migrate into freshwater systems via coastal streams and estuaries. As their spawning runs can cover great distances, some populations have historically branched out to form landlocked subpopulations.
Named for the deep and rounded shape of its body’s anterior region, its form has been likened to that of plump tavernkeepers (i.e. alewives). On average, it grows to a modest length of about 10 inches (25 cm). In Connecticut, the largest recorded size for a landlocked alewife is 11 inches (28 cm). Both anadromous and landlocked populations are preyed upon by larger sportfish. These populations are largely concentrated close to the state’s coastline.
