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The fish encyclopedia

The ocean, explained one fish at a time.

Species profiles, aquarium care and clear answers to the questions people ask about fish. Researched, fact checked and written for curious minds.

Freshwater Saltwater Aquarium fish Edible fish Deep sea

Unicornfish

Fish of the weekUnicorn fishRead the full profile →

Fish Finder

Find the right fish in seconds.

Filter every species by water type, size, temperament and care level. Perfect for planning a tank or identifying a catch.

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Four ways into the water

Whether you keep fish, catch them, cook them or simply wonder about them.

Unicornfish in dark water

A to Z encyclopediaFish SpeciesFreshwater, saltwater, aquarium and deep sea fish, each with a full profile.

Planted freshwater aquarium

Aquarium CareTanks, filters, water and tank mates

Striated frogfish

Fish FactsStrange, rare, surprising

Whole grilled fish on a plate

Fish as Food

Most searched this month

Blue betta fish

Betta fish

Betta splendens

EasyCare2.5 inAdult sizeFreshWater

Orangeband surgeonfish

Orangeband surgeonfish

Acanthurus olivaceus

ExpertCare14 inMax sizeReefHabitat

Blue African cichlids

Cichlid fish

Family Cichlidae

MediumCareVariesMax sizeFreshWater

Koi fish in a pond

Koi fish

Cyprinus rubrofuscus

MediumCareUp to 3 ftMax sizeFreshWater

A lush planted aquarium

Featured guideHow to set up a planted tank that stays clear

Aquarium Care

A calmer, clearer tank.

01The best fish tank filters for every tank size 02Why is my fish tank cloudy? Causes and fixes 03Betta fish tank mates: who can live with a betta 04How many fish can go in a 20 gallon tank?

All aquarium guides

Explore by depth

From sunlit reefs to the midnight zone

Sunlit coral reef with small orange fish

0 TO 200 MSunlight zoneCoral reefs, tuna and most of the fish people know.

A dense school of silver fish in open water

200 TO 1,000 MTwilight zoneDim light, glowing lanternfish and nightly migrations.

1,000 M AND BELOWMidnight zoneAnglerfish, gulper eels and life in total darkness.

Fish Facts

Questions you never knew you had

All fish facts →

A hairy striated frogfish on the seafloor

Most readFish with legsMeet the frogfish, mudskippers and batfish that walk the seafloor, and sometimes the shore.

Quick answerDo fish blink?Most fish have no eyelids. Here is what they do instead. ListThe rarest fish in the worldSpecies so rare only a handful of people have seen them.