Cyprinidae
Blacktip shiner
Lythrurus atrapiculus
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.
Blacktip shiner
Callichthyidae
blacktop corydoras
Corydoras acutus
Callichthyidae
Blackwater cory
Corydoras crimmeni
Salmonidae
Blaufelchen
Coregonus wartmanni
Cyprinidae
Bleeding shiner
Luxilus zonatus
Cyprinidae
Bleeker's Apollo Shark
Luciosoma bleekeri
Siluridae
Bleeker's Sheatfish
Phalacronotus bleekeri
Melanotaeniidae
Bleher's rainbowfish
Chilatherina bleheri
Percidae
Blenny darter
Etheostoma blennius
Heptapteridae
Blind catfish
Pimelodella kronei
Nemacheilidae
Blind cave loach
Nemacheilus troglocataractus
Acestrorhamphidae
Blind Cave Tetra
Astyanax mexicanus
Synbranchidae
Blind Eel
Rakthamichthys digressus
Nemacheilidae
Blind loach
Eidinemacheilus smithi
Mastacembelidae
Blind spiny eel
Mastacembelus brichardi
Synbranchidae
Blind Swamp Eel
Ophisternon infernale
Salmonidae
Bloater
Coregonus hoyi
Cichlidae
Blockhead Cichlid
Steatocranus tinanti
Acestrorhamphidae
Blood Red Tetra
Brittanichthys axelrodi
Acestrorhamphidae
Blood Tetra
Hyphessobrycon pyrrhonotus
Cichlidae
Blood-red Jewel Cichlid
Rubricatochromis lifalili
Percidae
Bloodfin darter
Nothonotus sanguifluus
Characidae
Bloodfin tetra
Aphyocharax anisitsi
Cichlidae
Bloodgill dwarf cichlid
Apistogramma acrensis
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.