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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

Rivers and lakes

Fresh water: rivers, streams, lakes and ponds. 136 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 AmazonGolden 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

Still to be written: Mekong giant catfish.

Further reading

GroupSharkRayCarpCatfishSalmonidHerringCodTunaPerch-likeCichlidReef fishEelFlatfishLivebearerAncientOther
UseFood fishFarmedAquarium fishSport fishingCulture and faithVenomous or dangerousInvasiveScience and research
OrderBest knownA to ZOldest firstNewest firstBy size
WorldNile perch Large freshwater predator native to Africa, now invasive in many lakes.Other · Rivers and lakes Southeast AsiaBumblebee goby Small striped freshwater and brackish gobies from AsiaOther · Rivers and lakes WorldSilver dollar Round, silver tropical fish related to piranhas, popular in aquariums.Other · Rivers and lakes 🇨🇳 China and 4 moreCelestial Eye goldfish Fancy goldfish with upward-facing telescope eyesOther · Rivers and lakes 🇺🇸 United States and 2 moreLongnose gar A primitive ray-finned fish with a long snout and armored scales found in North America.Other · Rivers and lakes · 1758 🇺🇸 United States and 2 moreGar Ancient armored fish with lung-like swim bladders found in North American waters.Ancient · Rivers and lakes · 1758 🇺🇸 United StatesMooneye A family of large-eyed North American fish known for their metallic eye shine.Other · Rivers and lakes · 1819 🇧🇼 Botswana and 1 moreAfrican tigerfish Predatory freshwater fish known for sharp teeth and leaping hunting behaviour.Other · Rivers and lakes · 1861 🇺🇬 Uganda and 2 moreSilver cyprinid A small pelagic fish from Lake Victoria that supports regional food security.Other · Rivers and lakes WorldLeopard bush fish A freshwater labyrinth fish from the Congo River basin kept in home aquariums.Other · Rivers and lakes 🇺🇬 UgandaNangnang fish A small freshwater fish from the Nile basin, prized as a fried snack in Uganda.Other · Rivers and lakes 🇺🇸 United States and 4 moreLargemouth bass A large freshwater predator native to North America, prized by anglers and invasive in many regions.Other · Rivers and lakes · 1802 🇺🇸 United StatesSpotted bass A North American freshwater fish known for dark spots below its lateral line.Other · Rivers and lakes 🇺🇸 United StatesGuadalupe bass A rare Texas endemic black bass prized by anglers for its fighting spirit.Other · Rivers and lakes 🇺🇸 United States and 1 moreMuskellunge Large freshwater predatory fish native to North America and the largest member of the pike family.Other · Rivers and lakes 🇸🇷 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 🇧🇷 Brazil and 3 moreTambaqui A large freshwater fish from South America known for its heavy body and seed-eating habits.Other · Rivers and lakes 🇧🇷 Brazil and 4 moreWolf fish A predatory freshwater ray-finned fish found across Central and South America.Other · Rivers and lakes 🇺🇸 United States and 1 moreDesert pupfish Small desert fish that survives extreme heat and saltOther · Rivers and lakes · 1853 🇺🇸 United States and 1 moreMexican tetra A freshwater characin with surface and blind cave forms, studied for evolutionary biology.Other · Rivers and lakes 🇺🇸 United StatesWhite sucker A common North American freshwater cypriniform fish with fleshy lips used for bottom feeding.Other · Rivers and lakes · 1803 🇺🇸 United StatesDelta smelt A tiny, endangered fish native to California's Sacramento-San Joaquin River Delta.Other · Rivers and lakes · 1963 Latin America and the CaribbeanLeporinus South American freshwater fish genus in the Anostomidae familyOther · Rivers and lakes Northern cavefish 🇺🇸 United StatesNorthern cavefish A blind fish living in caves of Kentucky and IndianaOther · Rivers and lakes 🇷🇺 RussiaComephorus Two species of pelagic sculpins endemic to Lake Baikal in Russia.Other · Rivers and lakes · 1800 🇨🇺 CubaCuban gar Large tropical freshwater predator native to western Cuba.Other · Rivers and lakes 🇧🇷 BrazilBanded leporinus A striped freshwater fish from the Amazon kept in home tanks and occasionally caught by anglers.Other · Rivers and lakes WorldSnakehead Elongated freshwater predators with air-breathing organs found in Asia and Africa.Other · Rivers and lakes WorldFeatherbacks and knifefishes Freshwater bony-tongued fishes with long anal finsOther · 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 EuropeEuropean bullhead Small freshwater sculpin found in European rivers and streams.Other · Rivers and lakes Southeast AsiaGiant snakehead A large freshwater predator from Southeast Asia known for air breathing and invasive potential.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 WorldMormyrus A genus of weakly electric freshwater fish known for their elongated snouts.Other · Rivers and lakes · 1758 🇨🇦 Canada and 1 moreGoldeye A silver freshwater fish known for its smoked culinary form.Other · Rivers and lakes 🇦🇹 Austria and 4 moreEuropean mudminnow Small freshwater fish from Central and Eastern EuropeOther · Rivers and lakes East AsiaAmur pike A spotted freshwater pike native to east Asia.Other · Rivers and lakes 🇷🇺 Russia and 3 moreBurbot A coldwater freshwater fish with a chin whisker, native to the Northern Hemisphere.Other · Rivers and lakes · 1758 🇧🇷 Brazil and 4 moreArapaima Giant air-breathing freshwater fish of the AmazonOther · Rivers and lakes · 1822 🇺🇸 United StatesWhite bass A silver-striped freshwater fish native to North American rivers and lakes.Other · Rivers and lakes WorldDanio A genus of small striped freshwater fish from Asia kept in aquaria.Other · Rivers and lakes · 1822 🇦🇺 Australia and 2 moreRainbowfish Small colourful freshwater fish from Australia and New GuineaOther · Rivers and lakes · 1894 🇦🇷 Argentina and 4 moreArgentinian silverside A large, adaptable silverside native to South America.Other · Rivers and lakes 🇯🇵 JapanJapanese rice fish Small freshwater fish native to Japan and a key model organism.Other · Rivers and lakes 🇧🇷 Brazil and 4 moreRed-bellied piranha A widespread South American freshwater fish known for its omnivorous diet and shoaling behavior.Other · Rivers and lakes 🇧🇷 Brazil and 1 moreRed-bellied Pacu A large South American freshwater fish related to piranhas, farmed for food and kept in aquariums.Other · Rivers and lakes WorldHeadstander South American freshwater fish known for swimming with their heads pointed downwards.Other · Rivers and lakes
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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.