Osphronemidae
Clownface Betta
Betta cracens
FISH SPECIES
Freshwater Fish
Freshwater fish spend all or part of their lives in rivers, lakes, streams and wetlands. The label describes an environment, not one branch of the fish family tree, so freshwater species include many unrelated shapes and lineages.
FISH ATLAS / FIELD GUIDEFreshwater FishIN THIS CHAPTER01 / Characteristics02 / Lifestyle03 / Species04 / Field notes
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01 / NATURAL HISTORY
Characteristics
Freshwater habitats contain far less salt than seawater and can change quickly with seasons, floods and drought. Fish living there use many different strategies, from streamlined bodies for current to barbels that help find food near the bottom.
- 01River fish
- 02Lake fish
- 03Stream fish
02 / LIFESTYLE
Lifestyle
Life in freshwater follows the movement of water and food. Some fish hold position in a current and intercept drifting prey; others search plants or sediment for a meal. Changes in flow and water level can open feeding grounds or trigger movements toward spawning areas. These behaviors reflect how fish balance hydrodynamic energy expenditure against food intake.
OBSERVATION INDEX
- Holding position in a current
- Feeding among plants or sediment
- Movement with changing water levels
03 / SPECIES
Representative species
Discover representative species illustrating the ecological diversity, morphologies and adaptations of this group.
Clownface Betta
Callichthyidae
Club cory
Corydoras solox
Siluridae
Club-barbel sheatfish
Ceratoglanis pachynema
Cyprinidae
Coad's riffle minnow
Alburnoides coadi
Percidae
Coal darter
Percina brevicauda
Terapontidae
Coal grunter
Hephaestus carbo
Mochokidae
Coas Synodontis
Synodontis obesus
Callichthyidae
Coast cory
Scleromystax prionotos
Percidae
Coastal darter
Etheostoma colorosum
Heptapteridae
Coastal Pencil Catfish
Acentronichthys leptos
Cichlidae
Cobalt Zebra Cichlid
Maylandia callainos
Cobitidae
Cobitis hangkugensis
Cobitis hankugensis
Astroblepidae
Cobre climbing catfish
Astroblepus phelpsi
Cyprinidae
Cochin Puffer
Pao cochinchinensis
Stevardiidae
Cochu's blue tetra
Boehlkea fredcochui
Acestrorhamphidae
Cocibolca's Tetra
Astyanax cocibolca
Cichlidae
Cockatoo cichlid
Apistogramma cacatuoides
Eleotridae
Cocos Sleeper
Eleotris tubularis
Acestrorhamphidae
Coffee-bean tetra
Hyphessobrycon takasei
Cyprinidae
Colchic nase
Chondrostoma colchicum
Cobitidae
Colchic Spined Loach
Cobitis satunini
Acestrorhamphidae
Colcibolca tetra
Astyanax nasutus
Percidae
Coldwater darter
Etheostoma ditrema
Acestrorhamphidae
colletti tetra
Moenkhausia collettii
04 / FIELD NOTES
A closer look
What makes a fish freshwater?
It is recorded from inland waters with low salinity for all or part of its life cycle.
Are all freshwater fish closely related?
No. Freshwater is a habitat category that includes many separate evolutionary groups.
Can freshwater fish survive in seawater?
Most cannot; without physiological adaptations to excrete excess salt, their cells rapidly lose water through osmosis and dehydrate in hypertonic seawater.