Estuaries and mangroves
Where rivers meet the sea: estuaries, backwaters and mangroves. 33 fish on EveryFish so far.
Brackish water is the mix of fresh and salt water found in estuaries, lagoons, backwaters and mangrove creeks, where rivers meet the sea. Its saltiness rises and falls with the tides and the seasons, so only fish that can cope with change live there all the time. These waters are rich in food from the land and the sea, and they act as nurseries for many fish that later live on coasts and reefs.
Fish that handle change
Brackish-water fish are euryhaline: they can adjust the salt balance of their bodies as the water changes. Mullets, milkfish, scats, barramundi and the pearlspot live in India's backwaters and lagoons, such as Vembanad in Kerala and Chilika in Odisha. Mudskippers climb out onto mangrove roots at low tide, breathing through their wet skin. Archerfish shoot down insects from overhanging leaves. Bull sharks swim from the sea into estuaries and far up rivers.
Farms and pressures
Coastal ponds that take in tidal water are used to farm fish and shrimp: the bheris of West Bengal, the pokkali fields of Kerala and the milkfish ponds of the Philippines and Indonesia. Estuaries are also where ports, cities and industries crowd, and many are polluted or reclaimed. Clearing mangroves for shrimp farms has removed nurseries for wild fish across tropical Asia, and dams upstream cut the fresh water that keeps estuaries brackish.
Famous estuaries and mangroves fish
Still to be written: Barramundi, Green chromide, Giant mudskipper, Scatophagus argus, Flathead grey mullet, Banded archerfish, Bull shark.
Further reading
🇺🇸 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
🇲🇽 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
🇺🇸 United StatesDelta smelt
A tiny, endangered fish native to California's Sacramento-San Joaquin River Delta.Other · Rivers and lakes · 1963
🇨🇺 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
WorldThree-spined stickleback
Small northern fish known for rapid evolution and complex breeding.Other · Rivers and lakes
🇸🇳 Senegal and 3 moreSenegal bichir
Ancient African fish that breathes air and walks on landAncient · Rivers and lakes
🇷🇺 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
🇲🇽 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
Photo credits on this page
The small pictures above come from Wikimedia Commons under free licences. Some are cropped to fit.
- Milkfish: Wiki Farazi, CC0, source
- Atlantic sturgeon: Jiaqian AirplaneFan, CC BY 3.0, source
- Shortnose sturgeon: Unknown author, Public domain, source
- Tropical gar: AlejandroLinaresGarcia, CC BY-SA 3.0, source
- Bichir: 5snake5, CC0, source
- Delta smelt: Peterson, B. Moose / U.S. Fish and Wildlife Service, Public domain, source
- Cuban gar: Poleta33, CC BY-SA 3.0, source
- Pupfish: P.V. Loiselle, CC BY-SA 3.0, source
- Three-spined stickleback: Gilles San Martin, CC BY-SA 2.0, source
- Ruffe: Tiit Hunt, CC BY-SA 3.0, 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
- Mosquitofish: NOZO, CC BY-SA 3.0, source
- Japanese rice fish: NOZO, CC BY 3.0, source
- Largescale four-eyes: Michael Gäbler, CC BY 3.0, source