Fish Encyclopedia
Search and identify 1,000+ fish species — freshwater, saltwater, reef, and pelagic — with habitat, size, diet, behavior, and how to tell them apart.
Keyhole Cichlid
A calm, mild-mannered South American cichlid named for the distinctive dark keyhole-shaped blotch on its flank, this species is known for its subdued coloration and unusually peaceful temperament.
freshwater
Marble Trout
Marble trout are a large, distinctively patterned native trout of the Balkan Peninsula, named for the marbled, olive-and-brown pattern covering their body, and are now considered vulnerable due to hybridization with introduced brown trout.
freshwater
Figure-Eight Puffer
A small brackish-water pufferfish named for the bold black figure-eight-shaped markings across its yellow-green back. Like other puffers, it can inflate its body with water as a defense against predators.
brackish
Estuarine Stonefish
A heavily camouflaged, encrusted-looking fish that lies motionless on muddy estuary and mangrove bottoms across the Indo-Pacific, bearing venomous dorsal spines as a natural defense.
brackish
European Anchovy
A slender, small-bodied schooling fish with a distinctive pointed snout and underslung mouth, found in enormous shoals along European and North African coasts and throughout the Mediterranean.
pelagic
Electric Eel
A long, air-breathing South American knifefish, not a true eel, famous for generating powerful electric discharges from specialized organs used to stun prey, navigate, and defend itself.
freshwater
Cisco
Cisco, also known as lake herring, are slender silvery relatives of whitefish that form large open-water schools in the cold lakes of the northern United States and Canada, feeding mainly on plankton.
freshwater
Brook Trout
A colorful char native to cold, clear streams of eastern North America, marked by worm-like back markings and red spots haloed in blue along its sides. It is highly sensitive to water quality and temperature.
freshwater
Butterfish
A disc-shaped, silvery schooling fish of the northwestern Atlantic shelf, the Butterfish migrates seasonally between inshore and offshore waters and often shelters near jellyfish as a juvenile.
pelagic
Bluehead Wrasse
A small, abundant Caribbean reef fish famous for changing color and sex as it matures, with terminal males developing a striking blue head and green body. It is one of the most numerous fish on western Atlantic reefs.
reef
Allis Shad
A large anadromous herring relative native to Europe's Atlantic coast, the Allis Shad spends most of its life at sea but migrates into large rivers each spring to spawn, forming runs that have been much reduced.
brackish
Big-belly Seahorse
The largest seahorse species in the world, recognized by its notably rounded, protruding belly and mottled brown-yellow coloration, found along the temperate coasts of Australia and New Zealand.
saltwater
Bala Shark
A torpedo-shaped, silver freshwater fish named for its shark-like body outline, though it is a true minnow relative, not a shark. Bold black margins on its fins make it a striking, fast-swimming schooler of Southeast Asian rivers.
freshwater
Asian Swamp Eel
A slender, limbless, snake-like eel native to rice paddies and marshes of East and Southeast Asia, known for its air-breathing ability and its establishment as an introduced species in parts of the southeastern United States.
freshwaterZebra Seahorse
A small, boldly striped seahorse endemic to northern Australian waters, patterned with fine dark bands that give it a distinctly zebra-like appearance.
reef
Waspfish
A camouflaged, spiny bottom-dweller with fan-like pectoral fins and a mottled reddish-brown pattern, resting on sand or rubble near reefs across the Indo-Pacific.
saltwaterTadpole Cod
The tadpole cod is a tiny, translucent Gadiform fish named for its tadpole-like shape, found in warm surface waters worldwide and distinguished by its thread-like forward pelvic fins.
pelagic
Smalltooth Sawfish
A Critically Endangered ray-relative with a long, tooth-lined saw-like snout, once common in warm western Atlantic coastal waters but now greatly reduced in range.
cartilaginous
Silver Scat
A disc-shaped, silvery fish marked with dark vertical bars, found schooling in brackish estuaries and mangroves across the Indo-Pacific and northern Australia.
brackishRibbon Halfbeak
An extraordinarily thin, ribbon-shaped halfbeak of the open ocean, with a long needle-like lower jaw and greatly elongated fins that let it skitter and glide across the surface.
pelagic
Plains Killifish
A slender, sand-colored killifish adapted to the wide, shallow, shifting-sand rivers of the North American Great Plains, marked with narrow dark vertical bars.
freshwater
Porkfish
A bright yellow Caribbean grunt marked by two bold black diagonal stripes across the head, forming large schools that shelter near reef structure by day.
reef
Ohio Lamprey
The Ohio lamprey is a parasitic, jawless fish native to medium and large rivers of the eastern United States, attaching to host fish with a toothed sucking disc to feed.
freshwater
Ocean Pout
An eel-like bottom-dweller of the northwestern Atlantic, the Ocean Pout produces natural antifreeze proteins that let it stay active in near-freezing winter waters.
saltwater