Loricariidae
Catfish
Rhinelepis aspera
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.
Catfish
Doradidae
Catfish
Rhinodoras dorbignyi
Loricariidae
Catfish
Ricola macrops
Loricariidae
Catfish
Spatuloricaria evansii
Loricariidae
Catfish
Spatuloricaria nudiventris
Mochokidae
Catfish
Synodontis membranaceus
Mochokidae
Catfish
Synodontis nigrita
Mochokidae
Catfish
Synodontis ocellifer
Amphiliidae
Catfish
Zaireichthys wamiensis
Nemacheilidae
Catfish-like loach
Triplophysa siluroides
Poeciliidae
cauca molly
Poecilia caucana
Gobiidae
Caucasian goby
Ponticola constructor
Gobionidae
Caucasian gudgeon
Gobio caucasicus
Cyprinidae
Cauvery garra
Garra mcclellandi
Balitoridae
Cave angel fish
Cryptotora thamicola
Cyprinidae
Cave Brook Carp
Neolissochilus subterraneus
Clariidae
Cave catfish
Clarias cavernicola
Siluridae
Cave sheatfish
Pterocryptis buccata
Cyprinidae
cavedano chub
Squalius squalus
Astroblepidae
Cayendelet climbing catfish
Astroblepus theresiae
Callichthyidae
Ceara bulldog cory
Aspidoras raimundi
Cottidae
Cedar sculpin
Cottus schitsuumsh
Zenarchopteridae
Celebes halfbeak
Nomorhamphus liemi
Adrianichthyidae
Celebes medaka
Oryzias celebensis
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.