Cichlidae
Doublebanded dwarf cichlid
Apistogramma diplotaenia
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.
Doublebanded dwarf cichlid
Cichlidae
Doublespot acara
Aequidens pallidus
Cyprinidae
Douro nase
Pseudochondrostoma duriense
Sisoridae
Dr. Surapol’s Bat Catfish
Oreoglanis sudarai
Salmonidae
Draa trout
Salmo multipunctatus
Cyprinidae
Dracula fish
Danionella dracula
Loricariidae
Dragon Pleco
Pseudacanthicus serratus
Stevardiidae
Dragonfin tetra
Pseudocorynopoma doriae
Cyprinidae
Drapefin barb
Oreichthys parvus
Auchenipteridae
Driftwood Catfish
Trachelyopterichthys anduzei
Auchenipteridae
Driftwood catfish
Trachelyopterus fisheri
Petromyzontidae
Drin Brook Lamprey
Eudontomyzon stankokaramani
Rhamphichthyidae
Drop Knifefish
Gymnorhamphichthys britskii
Cyprinidae
Drusian spring minnow
Pseudophoxinus drusensis
Salmonidae
Dryanin's char
Salvelinus drjagini
Siluridae
Dryzone butter catfish
Ompok ceylonensis
Siluridae
Du An Catfish
Silurus duanensis
Nothobranchiidae
Dubois' Panchax
Epiplatys duboisi
Auchenipteridae
Duck catfish
Ageneiosus ucayalensis
Percidae
Duck Darter
Etheostoma planasaxatile
Adrianichthyidae
Duck-billed Buntingi
Adrianichthys kruyti
Pimelodidae
Duckbill catfish
Sorubim lima
Apteronotidae
Duckbill Knifefish
Parapteronotus hasemani
Gobiidae
duckbill pugolovka
Anatirostrum profundorum
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.