Cyprinidae
Bornean Sultan Fish
Leptobarbus melanotaenia
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.
Bornean Sultan Fish
Gyrinocheilidae
Borneo algae-eater
Gyrinocheilus pustulosus
Osphronemidae
Borneo betta
Betta taeniata
Cyprinidae
Borneo Bonylipped Barb
Osteochilus pentalineatus
Cobitidae
Borneo Loach
Pangio shelfordii
Melanotaeniidae
Bosemani Rainbow
Melanotaenia boesemani
Poeciliidae
Bottle toothcarp
Tomeurus gracilis
Parodontidae
Bottom Characin
Parodon guyanensis
Percidae
Boulder darter
Etheostoma wapiti
Alestidae
Boulenger's Featherfin Tetra
Bryconaethiops boulengeri
Cichlidae
Boulenger's Shell-dweller
Lepidiolamprologus boulengeri
Mastacembelidae
Boulenger's spiny eel
Mastacembelus alboguttatus
Rhamphichthyidae
Bow knifefish
Rhamphichthys drepanium
Amiidae
bowfin
Amia calva
Amiidae
Bowfin
Amia ocellicauda
Cyprinidae
Bowstripe barb
Enteromius viviparus
Cyprinodontidae
Boxer Pupfish
Cyprinodon simus
Galaxiidae
Brachygalaxias
Brachygalaxias bullocki
Acestrorhamphidae
Branca
Oligosarcus robustus
Cyprinidae
brassy minnow
Hybognathus hankinsoni
Bagridae
Brazhnikov's catfish
Tachysurus brashnikowi
Loricariidae
Brazil-butterfly
Dekeyseria pulchra
Acestrorhamphidae
Brazilian Astyanax
Astyanax lacustris
Acestrorhamphidae
Brazilian blind characid
Stygichthys typhlops
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.