Bryconidae
Cascafe Brycon
Brycon atrocaudatus
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
SCROLL
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.
Cascafe Brycon
Callichthyidae
Cascarudo
Callichthys callichthys
Loricariidae
Cascudo Pit Bull
Parotocinclus jumbo
Gobionidae
Caspian gudgeon
Gobio holurus
Cyprinidae
Caspian kutum
Rutilus kutum
Salmonidae
Caspian salmon
Salmo ciscaucasicus
Gobiidae
Caspian tadpole goby
Benthophilus macrocephalus
Gobiidae
Caspian tubenose goby
Proterorhinus semipellucidus
Cyprinidae
Catalan chub
Squalius laietanus
Cyprinidae
Catalonian barbel
Barbus haasi
Goodeidae
Catarina Allotoca
Allotoca catarinae
Cyprinodontidae
Catarina pupfish
Megupsilon aporus
Acestrorhamphidae
Catemaco characin
Astyanax caballeroi
Poeciliidae
Catemaco Livebearer
Poeciliopsis catemaco
Auchenipteridae
Catfish
Ageneiosus militaris
Loricariidae
Catfish
Ancistrus hoplogenys
Auchenipteridae
Catfish
Auchenipterus nigripinnis
Claroteidae
Catfish
Auchenoglanis biscutatus
Aspredinidae
Catfish
Bunocephalus doriae
Clariidae
Catfish
Clarias agboyiensis
Clariidae
Catfish
Clarias laeviceps
Callichthyidae
Catfish
Corydoras undulatus
Sisoridae
Catfish
Gagata youssoufi
Sisoridae
Catfish
Glyptothorax cavia
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.