Percidae
Finescale saddled darter
Etheostoma osburni
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.
Finescale saddled darter
Goodeidae
Finescale Splitfin
Allodontichthys polylepis
Datnioididae
Finescale tigerfish
Datnioides microlepis
Gobionidae
Finestreaked Gudgeon
Gnathopogon taeniellus
Mochokidae
Finetooth squeaker
Synodontis vanderwaali
Gobiidae
Finke goby
Chlamydogobius japalpa
Atherinidae
Finke River hardyhead
Craterocephalus centralis
Osphronemidae
Fire Betta
Betta rutilans
Mastacembelidae
fire eel
Mastacembelus erythrotaenia
Cyprinidae
Fire fin barb
Pethia melanomaculata
Osphronemidae
Fire Red Licorice Gourami
Parosphromenus sumatranus
Barbuccidae
Fire-eyed loach
Barbucca diabolica
Percidae
Firebelly darter
Etheostoma pyrrhogaster
Acestrorhamphidae
Firefin Tetra
Hyphessobrycon igneus
Acestrorhamphidae
Firehead tetra
Petitella bleheri
Cyprinidae
Fireline Devario
Devario sondhii
Cichlidae
firemouth cichlid
Thorichthys meeki
Eleotridae
Firetailed gudgeon
Hypseleotris galii
Pimelodidae
Firewood catfish
Sorubimichthys planiceps
Mochokidae
Fischer's Victoria squeaker
Synodontis afrofischeri
Cichlidae
Fissi
Sarotherodon caroli
Cichlidae
Five-barred Lamprologus
Neolamprologus tretocephalus
Cyprinidae
Fiveband barb
Desmopuntius pentazona
Cichlidae
Flag acara
Laetacara curviceps
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.