Salmonidae
Bear Lake whitefish
Prosopium abyssicola
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.
Bear Lake whitefish
Loricariidae
Bearded catfish
Pseudancistrus barbatus
Gobiidae
Bearded Eel Goby
Trypauchenopsis intermedia
Cyprinidae
Beardless Barb
Cyclocheilichthys apogon
Cyprinidae
Bearn beaked dace
Leuciscus bearnensis
Cyprinidae
Beautiful Shiner
Cyprinella formosa
Cyprinidae
Bedrock Shiner
Notropis rupestris
Dichichthyidae
Beige bristle shark
Dichichthys bigus
Acestrorhamphidae
Belizean tetra
Astyanax belizianus
Cichlidae
Belly Crawler Pike Cichlid
Crenicichla punctata
Bagridae
Belly up
Chrysichthys nigrodigitatus
Cyprinidae
Bengal danio
Devario devario
Botiidae
Bengal loach
Botia dario
Cyprinidae
Bengala barb
Megarasbora elanga
Cichlidae
Beni Apisto
Apistogramma rubrolineata
Cyprinidae
Berg River Redfin
Pseudobarbus burgi
Cyprinidae
Bergama barb
Capoeta bergamae
Synbranchidae
Berlin’s bloodworm eel
Ophisternon berlini
Cyprinidae
bermejuela
Achondrostoma arcasii
Mormyridae
Bernhard's elephant-snout fish
Mormyrus bernhardi
Nothobranchiidae
Berthold's killi
Scriptaphyosemion bertholdi
Cyprinidae
Beyazsu chub
Alburnoides emineae
Cyprinidae
Beysehir dace
Squalius anatolicus
Cyprinidae
Beysehir nase
Chondrostoma beysehirense
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.