Cobitidae
Beysehir spined loach
Cobitis bilseli
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.
Beysehir spined loach
Gobionidae
Beyşehir gudgeon
Gobio microlepidotus
Erethistidae
Bi-color Catfish
Erethistoides infuscatus
Cynodontidae
Biara
Rhaphiodon vulpinus
Pseudopimelodidae
Bicolor Bumblebee Catfish
Microglanis iheringi
Cyprinidae
Bicolored Barb
Hypselobarbus bicolor
Ctenoluciidae
bicuda
Boulengerella cuvieri
Comephoridae
Big Baikal oilfish
Comephorus baikalensis
Poeciliidae
Big Bend gambusia
Gambusia gaigei
Heptapteridae
Big Eye Pimelodella
Pimelodella megalops
Cichlidae
Big Lip Pike Cichlid
Crenicichla tendybaguassu
Cichlidae
Big red cichlid
Paretroplus lamenabe
Acestrorhynchidae
Big-eyed Cachorro
Acestrorhynchus falcirostris
Cichlidae
Big-eyed Mouthbrooder
Callochromis macrops
Cichlidae
Big-eyed Xenotilapia
Xenotilapia sima
Cyprinidae
Big-Head Schizothoracin
Aspiorhynchus laticeps
Gobionidae
Big-headed Gudgeon
Gobiobotia macrocephala
Cichlidae
Big-mouth Hap
Tyrannochromis macrostoma
Cyprinidae
Bigeye chub
Hybopsis amblops
Cichlidae
Bigeye cichlid
Acaronia nassa
Latidae
Bigeye lates
Lates mariae
Cyprinidae
Bigeye Shiner
Notropis boops
Mochokidae
Bigeye squeaker
Synodontis alberti
Cyprinodontidae
Bighead Pupfish
Cyprinodon pachycephalus
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.