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SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It Again OceanEye to eye with Britain's hidden sharks at SharkAdemy - Oceanographic RiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at all OceanShedd Aquarium Sends Shark Eggs to Bolster Wild Populations SpeciesA 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 Conservation OceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray Area SpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow Reductions FisheriesAdams River Salmon Run in Thompson-Nicola IndiaHilsa production dropped 26% in five years, fisheries minister tells parliament SpeciesScientists Discover Mysterious New Fish in the Red Sea – and Have Never Seen It Again OceanEye to eye with Britain's hidden sharks at SharkAdemy - Oceanographic RiversIn October, biologists surveying a New York harbor for invasive fish pulled up a bright yellow one. It wasn't an invasive species at all OceanShedd Aquarium Sends Shark Eggs to Bolster Wild Populations SpeciesA 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 Conservation OceanEckerd College professor contributes to designating Biscayne Bay an Important Shark and Ray Area SpeciesRio Verde Grande Survey Identifies Fifty-Three Fish Species Facing Flow Reductions FisheriesAdams River Salmon Run in Thompson-Nicola IndiaHilsa production dropped 26% in five years, fisheries minister tells parliament

EveryFish

Small: 5 to 20 cm

Sardines, anchovies, most aquarium fish and many reef fish. 56 fish.

Tiny Small Medium Large Very large Giant

🇺🇸 United StatesDelta smelt A tiny, endangered fish native to California's Sacramento-San Joaquin River Delta.Other · Rivers and lakes · 1963

WorldThree-spined stickleback Small northern fish known for rapid evolution and complex breeding.Other · 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 States and 4 moreMosquitofish Small North American fish introduced globally for mosquito control.Livebearer · Rivers and lakes

South AsiaGreen spotted puffer Small brackish water pufferfish with a tiny genomeOther · Rivers and lakes

🇲🇽 Mexico and 1 moreGreen swordtail A hardy live-bearing fish popular in home aquariums.Livebearer · Rivers and lakes · 1848

Photo credits on this page

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

Delta smelt: Peterson, B. Moose / U.S. Fish and Wildlife Service, Public domain, source
Three-spined stickleback: Gilles San Martin, CC BY-SA 2.0, source
Xiphophorus: Marrabbio2, CC BY-SA 3.0, source
Killifish: TinoStrauss, CC BY-SA 3.0, source
Mosquitofish: NOZO, CC BY-SA 3.0, source
Green spotted puffer: Starseed, CC BY-SA 3.0 de, source
Green swordtail: Bastet78, CC BY-SA 3.0, source

The weekly digest

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