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
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Rivers and lakes

Fresh water: rivers, streams, lakes and ponds. 314 fish on EveryFish so far.

Rivers, lakes, streams and ponds hold less than one per cent of the Earth's water, yet about half of all known fish species live in them. Fresh water is broken into separate basins, and fish that cannot cross between them evolve apart, which is why each river system and lake has its own species. The Amazon, Congo, Mekong and Ganges basins and the great lakes of Africa are the richest.

Life in fresh water

A freshwater fish is saltier inside than the water around it, so it must pump salt in through its gills and pass a lot of dilute urine. Freshwater habitats range from torrential Himalayan streams, where loaches cling to rocks, to warm, still swamps where air-breathing snakeheads, catfish and gouramis thrive. Many river fish time their spawning to floods: the Indian major carps spawn in the monsoon floodwaters, and Mekong fish move into flooded forests.

The most threatened fish

Freshwater fish are declining faster than sea fish. A 2021 report by conservation groups found that about a third of freshwater fish species are threatened with extinction and that 80 had already been declared extinct. Dams block migrations, water is drawn off for farms and cities, pollution and sand mining degrade rivers, and introduced species such as tilapia and African catfish compete with native fish. In India, the rivers of the Western Ghats and the North-East hold many endemic fish at risk.

Famous rivers and lakes fish

RohuA river carp of the Indian subcontinentArapaimaAn air-breathing giant of the AmazonMekong giant catfishOne of the largest freshwater fishGolden mahseerThe golden mahseer of Himalayan riversNile perchA huge predator of African lakesRed-bellied piranhaA schooling fish of South American riversZebrafishA small fish of South Asian streams

Further reading

GroupSharkRayCarpCatfishSalmonidHerringCodTunaPerch-likeCichlidReef fishEelFlatfishLivebearerAncientOther
UseFood fishFarmedAquarium fishSport fishingCulture and faithVenomous or dangerousInvasiveScience and research
OrderBest knownA to ZOldest firstNewest firstBy size
🇸🇷 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 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 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 🇧🇷 Brazil and 4 moreHoplias aimara A large freshwater predator from South America known for its size and mercury accumulation.Other · Rivers and lakes · 1846 🇯🇵 JapanJapanese rice fish Small freshwater fish native to Japan and a key model organism.Other · Rivers and lakes 🇵🇦 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 South AsiaGreen spotted puffer Small brackish water pufferfish with a tiny genomeOther · Rivers and lakes Sub-Saharan AfricaFreshwater butterflyfish Surface-dwelling African fish that glides above water.Other · Rivers and lakes 🇰🇭 Cambodia and 3 moreMoonlight gourami A small, silvery labyrinth fish native to Southeast Asian rivers and swamps.Other · Rivers and lakes 🇨🇳 China and 1 moreParadise fish Aggressive freshwater gourami from East AsiaOther · Rivers and lakes 🇺🇸 United States and 1 moreRazorback sucker Endangered river fish with a distinctive back ridgeOther · Rivers and lakes 🇺🇸 United StatesDevils Hole pupfish A tiny fish found only in one cavern in Nevada.Other · Rivers and lakes · 1930 🇬🇧 United Kingdom and 4 moreStone loach A small European freshwater fish that hides under gravel and hunts at night.Other · Rivers and lakes

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

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