Percidae
Corrugated darter
Etheostoma basilare
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.
Corrugated darter
Salmonidae
Coruh trout
Salmo coruhensis
Cichlidae
Corumba cichlid
Apistogramma commbrae
Badidae
Cory Badis
Badis corycaeus
Petromyzontidae
Costa de Prata Lamprey
Lampetra alavariensis
Bryconidae
Costa Rican Brycon
Brycon costaricensis
Acestrorhamphidae
Costa Rican tetra
Astyanax orstedii
Acestrorhamphidae
Costa's Tetra
Moenkhausia costae
Acestrorhamphidae
Costello tetra
Hemigrammus hyanuary
Cyprinidae
Cotio
Osteobrama cotio
Loricariidae
couchu
Chaetostoma fischeri
Eleotridae
Cox's gudgeon
Gobiomorphus coxii
Bryconidae
Coxey's Brycon
Brycon coxeyi
Eleotridae
Cran's bully
Gobiomorphus basalis
Cyprinidae
creek chub
Semotilus atromaculatus
Nemacheilidae
Creek loach
Schistura beavani
Stevardiidae
Creek tetra
Bryconamericus scleroparius
Stevardiidae
Creek tetra
Bryconamericus terrabensis
Acestrorhamphidae
Creole Astyanax
Astyanax angustifrons
Aspredinidae
Creole Banjo
Bunocephalus aloikae
Percidae
Creole darter
Etheostoma collettei
Acestrorhamphidae
Creole Jupiaba
Jupiaba abramoides
Percichthyidae
Creole perch
Percichthys trucha
Poeciliidae
Creole topminnow
Girardinus creolus
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.