Syngnathidae
Dumbéa river pipefish
Microphis cruentus
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.
Dumbéa river pipefish
Auchenipteridae
Dunn's Tatia
Tatia dunni
Cyprinidae
Durango Shiner
Notropis aulidion
Cyprinodontidae
Durophage pupfish
Cyprinodon brontotheroides
Acestrorhamphidae
Dusky Astyanax
Psalidodon leonidas
Osphronemidae
Dusky betta
Betta fusca
Percidae
Dusky darter
Percina sciera
Cyprinidae
Dusky Face Carp
Osteochilus lini
Galaxiidae
Dusky galaxias
Galaxias pullus
Goodeidae
Dusky Goodea
Goodea gracilis
Characidae
Dusky Headstander
Charax tectifer
Cyprinidae
Dusky labiate-barbel
Semilabeo obscurus
Triportheidae
Dusky Narrow Hatchetfish
Triportheus angulatus
Cyprinidae
Dusky shiner
Notropis cummingsae
Auchenipteridae
Dusky Tatia
Tatia nigra
Heptapteridae
Dusky Three-bearded Catfish
Rhamdia nicaraguensis
Ambassidae
Duskyfin glassy perchlet
Parambassis wolffii
Cyprinidae
Duskystripe shiner
Luxilus pilsbryi
Percidae
Duskytail darter
Etheostoma percnurum
Cyprinidae
Dwarf Altai osman
Oreoleuciscus humilis
Cichlidae
Dwarf Angelfish
Pterophyllum leopoldi
Cyprinidae
Dwarf barb
Enteromius brevidorsalis
Bagridae
Dwarf bumblebee catfish
Pseudomystus leiacanthus
Bagridae
Dwarf catfish
Tachysurus argentivittatus
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.