Potamotrygonidae
Largespot river stingray
Potamotrygon falkneri
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.
Largespot river stingray
Mochokidae
Largespot squeaker
Synodontis macrostigma
Acestrorhamphidae
Largespot tetra
Astyanax orthodus
Channidae
Largespotted snakehead
Parachanna insignis
Poeciliidae
Largespring gambusia
Gambusia geiseri
Poeciliidae
Largetooth limia
Limia grossidens
Cichlidae
Larvophile dwarf cichlid
Apistogramma barlowi
Acestrorhamphidae
Lateral striped tetra
Astyanax lineatus
Stevardiidae
Latin Astyanax
Bryconamericus poi
Cichlidae
lattice dwarf cichlid
Nannacara taenia
Alestidae
Lattice Robber
Micralestes humilis
Cichlidae
Latticed Cichlid
Limnotilapia dardennii
Cichlidae
Lavender mbuna
Iodotropheus sprengerae
Cichlidae
Lawsi Cichlid
Gephyrochromis lawsi
Cyprinidae
Layardi’s barb
Puntius layardi
Cyprinidae
Leaden Labeo
Labeo molybdinus
Nandidae
Leaf fish
Nandus andrewi
Cyprinidae
Leaping barb
Laubuka caeruleostigmata
Petromyzontidae
Least brook lamprey
Lampetra aepyptera
Cyprinidae
Least chub
Iotichthys phlegethontis
Percidae
Least darter
Etheostoma microperca
Ictaluridae
Least madtom
Noturus hildebrandi
Lebiasinidae
Least pencilfish
Nannostomus minimus
Cyprinidae
Least rasbora
Boraras urophthalmoides
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.