Rivers and lakes
Fresh water: rivers, streams, lakes and ponds. 635 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 subcontinent
ArapaimaAn air-breathing giant of the Amazon
Mekong giant catfishOne of the largest freshwater fish
Golden mahseerThe golden mahseer of Himalayan rivers
Nile perchA huge predator of African lakes
Red-bellied piranhaA schooling fish of South American rivers
ZebrafishA small fish of South Asian streamsFurther reading
🇹🇭 Thailand and 4 moreSiamese fighting fish
A small, colorful freshwater fish native to Southeast Asia, famous as a pet and for male aggression.Livebearer · Rivers and lakes · 1910
🇻🇪 VenezuelaEndler's livebearer
A small, colourful freshwater fish from Venezuela known for its bright patterns and ease of breeding in home aquariums.Livebearer · Rivers and lakes · 2005
WorldAphyosemion
A large genus of small African killifish kept in home aquariums.Livebearer · Rivers and lakes
🇲🇽 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
🇧🇷 Brazil and 1 moreLargescale four-eyes
Surface-dwelling fish with split eyes for dual vision.Livebearer · Rivers and lakes · 1758
🇲🇽 MexicoButterfly splitfin
A critically endangered livebearing fish from Mexico.Livebearer · Rivers and lakes · 1971
WorldTetra
Common name for small freshwater characiform fishes popular in aquaria.Livebearer · Rivers and lakes
🇵🇬 Papua New GuineaForktail blue-eye
A small freshwater fish from Papua New Guinea rainforests.Livebearer · Rivers and lakes
🇲🇿 MozambiqueBluefin notho
A small annual killifish from Mozambique kept in aquaria.Livebearer · Rivers and lakes · 1926
🇬🇦 GabonLyretail panchax
Small colourful freshwater killifish from GabonLivebearer · Rivers and lakes
🇬🇳 Guinea and 2 moreClown killi
Small West African freshwater fish with ringed patternsLivebearer · Rivers and lakes · 1915
🇳🇬 Nigeria and 1 moreBlue lyretail
A colourful West African killifish kept in home aquariums.Livebearer · Rivers and lakes · 1911
🇲🇽 Mexico and 2 moreMexican molly
Small livebearing fish from Mexico and Central America.Livebearer · Rivers and lakes
🇺🇸 United States and 1 moreSailfin molly
Small livebearing fish with a large dorsal fin in males.Livebearer · Rivers and lakes · 1821
🇲🇽 Mexico and 1 moreSouthern platyfish
Small live-bearing freshwater fish from Central AmericaLivebearer · Rivers and lakes
🇲🇽 MexicoVariable platyfish
Small livebearing fish from Mexico popular in home aquariumsLivebearer · Rivers and lakes
🇲🇽 Mexico and 1 moreGreen swordtail
A hardy live-bearing fish popular in home aquariums.Livebearer · Rivers and lakes · 1848
🇹🇿 TanzaniaRedtail notho
A small annual killifish from ZanzibarLivebearer · Rivers and lakes
🇻🇪 Venezuela and 4 moreGuppy
Small tropical livebearer known for bright male colours and rapid reproduction.Livebearer · Rivers and lakes · 1859
🇺🇸 United StatesFlagfish
Small Florida pupfish with a US flag patternLivebearer · Rivers and lakes · 1879
Photo credits on this page
The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.
- Rohu: Wiki Farazi, CC0, source
- Nile perch: Pavel Zuber, CC BY-SA 3.0, source
- Siamese fighting fish: Henryk Niestrój, CC BY 4.0, source
- Endler's livebearer: Marrabbio2, CC BY-SA 3.0, source
- Arapaima: This illustration was made by Citron You must credit this : Citron / C, CC BY-SA 3.0, source
- Zebrafish: Roundish, CC0, source
- Aphyosemion: Violaine2, CC BY 3.0, source
- Golden mahseer: Khalid Mahmood, CC BY-SA 4.0, source
- Xiphophorus: Marrabbio2, CC BY-SA 3.0, source
- Killifish: TinoStrauss, CC BY-SA 3.0, source
- Least killifish: Brian Gratwicke, CC BY 2.0, source
- Largescale four-eyes: Michael Gäbler, CC BY 3.0, source
- Red-bellied piranha: Gregory Moine, CC BY 2.0, source
- Butterfly splitfin: Przemysław Malkowski, CC BY-SA 3.0, source
- Tetra: Holger Krisp, CC BY 3.0, source
- Forktail blue-eye: Dirk Godlinski, CC BY-SA 3.0, source
- Lyretail panchax: Alexander Prokoshev, CC BY-SA 3.0, source
- Clown killi: Oscar le poisson, CC BY-SA 3.0, source
- Blue lyretail: Violaine2, France, CC BY-SA 3.0, source
- Mexican molly: Taken by Darkmax, CC BY-SA 3.0, source
- Sailfin molly: (c) Nick Tobler (Cowturtle), some rights reserved (CC BY), CC BY 4.0, source
- Southern platyfish: Photograph by Jere Kyyrö. Uploaded by Rasvis ., CC BY-SA 3.0, source
- Green swordtail: Bastet78, CC BY-SA 3.0, source
- Mekong giant catfish: KKPCW, CC BY-SA 4.0, source
- Redtail notho: Jokuyken15, CC BY 4.0, source
- Guppy: Wibowo Djatmiko ( Wie146 ), CC BY-SA 3.0, source