News
SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It AgainOceanEye to eye with Britain's hidden sharks at SharkAdemy - OceanographicRiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at allOceanShedd Aquarium Sends Shark Eggs to Bolster Wild PopulationsSpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for ConservationOceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray AreaSpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow ReductionsFisheriesAdams River Salmon Run in Thompson-NicolaIndiaHilsa production dropped 26% in five years, fisheries minister tells parliamentSpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It AgainOceanEye to eye with Britain's hidden sharks at SharkAdemy - OceanographicRiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at allOceanShedd Aquarium Sends Shark Eggs to Bolster Wild PopulationsSpeciesA rare fish has been found in Lake Ontario, North America, whose entire body is golden. It is a nati..OceanThe Great Sea Reef Is Fiji’s Wildest Dive, and a New Frontier for ConservationOceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray AreaSpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow ReductionsFisheriesAdams River Salmon Run in Thompson-NicolaIndiaHilsa production dropped 26% in five years, fisheries minister tells parliament
EveryFish

Science and research

Model organisms and fish famous in science. 55 fish on EveryFish so far.

Fish are important in science. Some species are model organisms, small, fast-breeding fish that are studied in depth in laboratories to understand biology in general, from how embryos grow to how genes cause disease. Others are famous for what they reveal about evolution, such as the coelacanth, the blind cave fish and the cichlids of the African lakes. Fish also help scientists monitor the health of rivers and seas.

Zebrafish and medaka

The zebrafish, a small striped danio of South Asian streams, became a major model organism from the 1970s and 1980s. Its embryos are see-through and grow outside the mother, so scientists can watch organs and nerves form under the microscope. It is used to study development, heart and nerve disease, cancer and the effects of drugs and pollutants. The Japanese medaka is another model, and in 1994 medaka became the first vertebrates to mate and produce young in orbit, on a Space Shuttle flight.

Fish that explain evolution

The three-spined stickleback has repeatedly lost its bony armour after moving from the sea into lakes, letting scientists trace the genes involved. Sighted and blind forms of the Mexican tetra show how eyes are lost in caves. The turquoise killifish, which lives only a few months, is used to study ageing. The coelacanth and lungfish shed light on how fish first moved onto land, and the spotted gar's genome helps link fish genes to human ones.

Famous science and research fish

ZebrafishA leading model organismJapanese rice fishThe medaka, first vertebrate to breed in orbitMexican tetraSighted and blind formsThree-spined sticklebackA model of evolution in actionSpotted garIts genome bridges fish and human genesWest Indian Ocean coelacanthA window on the move to land

Still to be written: Nothobranchius furzeri, Guppy.

Further reading

GroupSharkRayCarpCatfishSalmonidHerringCodTunaPerch-likeCichlidReef fishEelFlatfishLivebearerAncientOther
WaterRivers and lakesEstuaries and mangrovesCoasts and shelvesCoral reefsOpen oceanDeep seaPolar and cold seasCaves and springsBetween sea and river
OrderBest knownA to ZOldest firstNewest firstBy size
🇺🇸 United States and 4 moreSea lamprey A jawless, parasitic fish native to the Northern Hemisphere that attacks other fish.Ancient · Rivers and lakes · 1758 🇺🇸 United States and 1 moreAtlantic sturgeon A large anadromous fish native to the western Atlantic Ocean and its river systems.Ancient · Rivers and lakes 🇺🇸 United States and 1 moreShortnose sturgeon A small, endangered North American sturgeon with a short snout.Ancient · Rivers and lakes · 1818 🇺🇸 United StatesPallid sturgeon An endangered North American sturgeon species native to the Missouri and Mississippi river basins.Ancient · Rivers and lakes · 1905 🇲🇽 Mexico and 2 moreTropical gar A small freshwater predator from Central America known for its armored scales and air-breathing ability.Ancient · Rivers and lakes WorldLamprey Jawless fish with a sucking mouth found in temperate waters worldwide.Ancient · Rivers and lakes 🇳🇬 NigeriaGymnarchus African electric fish with a long dorsal fin used for swimming and sensing prey.Ancient · Rivers and lakes · 1829 WorldHaplochromis A large ray-finned fish genus from East Africa known for rapid evolution and aquarium popularity.Cichlid · Rivers and lakes · 1888 🇸🇷 Suriname and 2 moreRedeye piranha A large freshwater fish from South America with a rhombus-shaped body and red eyes.Other · Rivers and lakes · 1766 🇺🇸 United States and 1 moreMexican tetra A freshwater characin with surface and blind cave forms, studied for evolutionary biology.Other · Rivers and lakes 🇺🇸 United StatesDelta smelt A tiny, endangered fish native to California's Sacramento-San Joaquin River Delta.Other · Rivers and lakes · 1963 🇺🇸 United StatesAmerican paddlefish Ancient freshwater fish with a sensory snout and filter-feeding habits.Ancient · Rivers and lakes · 1792 Northern cavefish 🇺🇸 United StatesNorthern cavefish A blind fish living in caves of Kentucky and IndianaOther · Rivers and lakes 🇨🇺 CubaCuban gar Large tropical freshwater predator native to western Cuba.Other · Rivers and lakes 🇺🇸 United States and 2 morePupfish Small killifish known for surviving in extreme isolated waters.Livebearer · Rivers and lakes 🇮🇳 India and 4 moreZebrafish Small striped fish from South Asia kept in aquariums and labsCarp · Rivers and lakes WorldThree-spined stickleback Small northern fish known for rapid evolution and complex breeding.Other · Rivers and lakes WorldNinespine stickleback Small freshwater fish with variable spines found across the Northern Hemisphere.Other · Rivers and lakes Titicaca orestias 🇵🇪 Peru and 1 moreTiticaca orestias Largest killifish of Lake Titicaca, likely extinct.Livebearer · Rivers and lakes 🇧🇷 Brazil and 4 moreHoplias aimara A large freshwater predator from South America known for its size and mercury accumulation.Other · Rivers and lakes · 1846 🇧🇷 Brazil and 1 moreElectric eel Neotropical freshwater fish capable of generating powerful electric shocks for hunting and defence.Eel · Rivers and lakes · 1766 🇦🇺 AustraliaAustralian lungfish Ancient air-breathing fish endemic to Queensland rivers, known for its longevity and living fossil status.Ancient · Rivers and lakes · 1871 🇷🇺 Russia and 1 moreRuffe A small, aggressive freshwater fish native to Eurasia that has become a major invasive pest in North America.Perch-like · Rivers and lakes · 1758 🇺🇸 United States and 1 morePacific lamprey An anadromous parasitic jawless fish found along the Pacific Rim.Ancient · Rivers and lakes · 1872 🇲🇽 Mexico and 3 moreXiphophorus A genus of small livebearing fish native to Mexico and Central America, known for aquarium use and genetic research.Livebearer · Rivers and lakes WorldKillifish Small egg-laying fish known for hardiness and short lifespansLivebearer · Rivers and lakes 🇺🇸 United StatesLeast killifish A tiny North American fish that gives birth to live young and measures just two centimetres long.Livebearer · Rivers and lakes 🇺🇸 United States and 4 moreMosquitofish Small North American fish introduced globally for mosquito control.Livebearer · Rivers and lakes 🇯🇵 JapanJapanese rice fish Small freshwater fish native to Japan and a key model organism.Other · Rivers and lakes 🇧🇷 Brazil and 1 moreLargescale four-eyes Surface-dwelling fish with split eyes for dual vision.Livebearer · Rivers and lakes · 1758 🇵🇦 Panama and 1 moreGlass knifefish Translucent electric fish from South American riversOther · Rivers and lakes 🇺🇸 United StatesSouthern cavefish A blind cavefish from the eastern United States.Other · Rivers and lakes · 1859 🇸🇳 Senegal and 3 moreSenegal bichir Ancient African fish that breathes air and walks on landAncient · Rivers and lakes South AsiaGreen spotted puffer Small brackish water pufferfish with a tiny genomeOther · Rivers and lakes

Photo credits on this page

The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.

The weekly digest

Every Monday: the fish of the day, new pages on EveryFish, and the conferences and anniversaries of the week ahead.