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.
Atlantic Herring
A slender, silvery schooling fish that forms some of the largest shoals in the North Atlantic, feeding on plankton and serving as a key forage species for larger fish, seabirds, and marine mammals.
pelagic
Australian Rainbowfish
A widespread, variably colored rainbowfish found across tropical Australian and southern New Guinea waterways, ranging from olive-silver to vivid blue and yellow forms.
freshwater
Mosquitofish
A small, drab livebearer native to the central and southeastern United States, the mosquitofish is famous for its voracious appetite for mosquito larvae and has been introduced worldwide for pest control.
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
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
Wels Catfish
One of the largest freshwater fish in the world, the wels catfish is a scaleless, elongated predator native to European rivers and lakes, recognizable by its enormous flattened head and long barbels.
freshwater
Threadfin Shad
A small, deep-bodied herring relative native to the Gulf Coast and Mississippi basin, the Threadfin Shad is widely stocked in freshwater reservoirs across the United States as an important forage fish.
freshwater
Smallmouth Bass
A bronze-green freshwater bass native to eastern North America, prized as a popular sport fish and recognized by its vertical dark bars and reddish eyes. It favors clear, rocky rivers, streams, and lakes.
freshwater
Red Lionfish
Instantly recognizable for its fan-like, striped fins and venomous spines, the red lionfish is a native Indo-Pacific reef predator that has become a damaging invasive species in the Western Atlantic.
reef
Poor Cod
The poor cod is a small, golden-brown Gadidae common around rocky reefs and harbors of the northeastern Atlantic and Mediterranean, identified by its short chin barbel and dark pectoral-fin blotch.
saltwater
Reticulated Hillstream Loach
The Reticulated Hillstream Loach is a flat, disc-shaped fish from Vietnamese mountain streams, patterned with an intricate net-like design and adapted to cling to rocks in swift current.
freshwater
Pacific Herring
A slender, silvery schooling fish closely related to the Atlantic Herring, found in cold coastal waters across the North Pacific, where it forms a critical forage base for fish, seabirds, and marine mammals.
pelagic
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.
freshwaterIndian Oil Sardine
A small, oil-rich pelagic fish abundant along India's western coast and the wider northern Indian Ocean, the Indian Oil Sardine forms massive schools and is one of the region's most heavily monitored fisheries species.
pelagic
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
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
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
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
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
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
Black Ghost Knifefish
A uniformly black, blade-shaped freshwater fish that swims using a long undulating ventral fin and navigates using a weak electric field generated along its body.
freshwater
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.
brackish