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.
Mono
A shimmering, disc-shaped fish with a strongly flattened body and tall, angular fins, native to Indo-Pacific estuaries. Adults school in brackish coastal waters and shift gradually toward full seawater as they mature.
brackish
Mono Argentus
A flat, disc-shaped, mirror-silver fish with tall yellow-tinged fins, commonly seen schooling in brackish estuaries and harbors across the Indo-Pacific.
brackish
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
Green Chromide
A deep-bodied cichlid from South Asian estuaries, olive-green with rows of shimmering pearly spots along its flanks. It is one of the largest brackish-water cichlids and an important species in coastal lagoon ecosystems.
brackish
Alligator Gar
A massive, armor-scaled freshwater fish with a broad alligator-like snout lined with two rows of sharp teeth, among the largest freshwater fish in North America.
freshwater
Timor Halfbeak
A small, slender halfbeak of the genus Zenarchopterus with a needle-thin lower jaw, common in the brackish estuaries and coastal rivers of the Indo-Pacific near Timor and Southeast Asia.
brackish
Sailfin Molly
Named for the male's spectacular, sail-like dorsal fin, this coastal livebearer from the southeastern United States and Mexico is a striking sight in brackish marshes and aquariums alike.
brackish
Gilthead Bream
A deep-bodied Mediterranean and Eastern Atlantic sparid named for the golden band across its forehead. A euryhaline species that moves between coastal reefs and brackish lagoons.
saltwater
Colombian Shark Catfish
A sleek, silver, shark-shaped catfish with a tall dorsal fin and long barbels, native to brackish river mouths along the Pacific coast of Central and South America.
brackish
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
Molly
A hardy, adaptable livebearer native to Mexico and Central America, the common molly thrives in fresh, brackish, and even marine water and is one of the most popular beginner aquarium fish.
freshwater
Wrestling Halfbeak
Named for the ritualized jaw-locking contests between rival males, the wrestling halfbeak is a slender surface-dwelling fish from Southeast Asian creeks and mangrove-fringed brackish waters.
brackish
Baltic Herring
A smaller, brackish-water subspecies of the Atlantic Herring, the Baltic Herring is adapted to the low-salinity Baltic Sea and forms one of the region's most abundant and ecologically important schooling fish.
brackish
Gulf Pipefish
The Gulf pipefish is a small, slender pipefish common in seagrass beds and estuaries around the Gulf of Mexico and southeastern United States, notable for tolerating salinities ranging from full seawater to nearly fresh water.
brackish
Spotted Scat
A deep-bodied, disc-shaped fish covered in dark spots over an olive-to-silver background, common in Indo-Pacific estuaries and harbors. Its bold pattern and spiny dorsal fin make it easy to pick out among schooling brackish fish.
brackish
Green Scat
A green-toned color variant of the Spotted Scat, with the same deep, disc-shaped body but a more uniform olive-green wash and lighter spotting. Found in the same brackish estuaries and harbors across the Indo-Pacific.
brackish
Iridescent Shark
Despite its name, this is a large freshwater catfish, not a shark, recognized in juveniles by an iridescent sheen and dark stripes that fade with age.
freshwater
Electric Catfish
An African freshwater catfish capable of generating strong electric discharges from specialized body tissue used for hunting and defense.
freshwater
Goldfish
A hardy freshwater fish domesticated from the wild Prussian carp, prized worldwide as an ornamental pond and aquarium species in many color forms.
freshwater
Common Roach
A widespread European freshwater fish with a silvery body and distinctive red-orange fins, forming large shoals in slow rivers, lakes, and canals.
freshwater
Betta
A small, vividly colored Southeast Asian freshwater fish famed for its flowing fins and the intense territorial aggression of males toward rivals.
freshwater
Ember Tetra
A tiny, glowing orange-red tetra that shoals in large numbers and is among the smallest characins kept in freshwater aquaria.
freshwater
Dwarf Pufferfish
The Dwarf Pufferfish is one of the world's smallest puffers, a freshwater species from southern India prized for its tiny size and expressive, alert behavior.
freshwater
Arapaima
One of the largest freshwater fish in the world, this massive Amazonian species has thick armor-like scales and must surface periodically to breathe air.
freshwater