Cyprinidae
Eastern Cape Redfin
Pseudobarbus afer
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.
Eastern Cape Redfin
Cobitidae
Eastern Carpathian golden loach
Sabanejewia vallachica
Cyprinidae
Eastern Chubbyhead Barb
Enteromius mandelai
Catostomidae
Eastern creek chubsucker
Erimyzon oblongus
Nemacheilidae
Eastern crested loach
Paracobitis longicauda
Galaxiidae
Eastern dwarf galaxias
Galaxiella pusilla
Percichthyidae
Eastern freshwater cod
Maccullochella ikei
Cichlidae
Eastern happy
Astatotilapia calliptera
Poeciliidae
Eastern Honduras molly
Poecilia hondurensis
Melanotaeniidae
Eastern rainbow fish
Melanotaenia splendida
Amphiliidae
Eastern sand catlet
Zaireichthys monomotapa
Percidae
Eastern sand darter
Ammocrypta pellucida
Cyprinidae
Eastern silvery minnow
Hybognathus regius
Percidae
Eastrim Darter
Etheostoma orientale
Cyprinidae
Ebro Barbel
Luciobarbus graellsii
Cyprinidae
Ebro nase
Parachondrostoma miegii
Nothobranchiidae
Edea killi
Aphyosemion edeanum
Gobiidae
Edgbaston goby
Chlamydogobius squamigenus
Osphronemidae
Edith's Mouthbrooder
Betta edithae
Clariidae
Eel catfish
Channallabes apus
Cobitidae
eel loach
Pangio anguillaris
Plotosidae
Eel-tailed catfish
Tandanus tandanus
Adrianichthyidae
Egg-carrying buntingi
Adrianichthys oophorus
Aspredinidae
Egg-eater Banjo
Amaralia oviraptor
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.