Serrasalmidae
Cardinal Pacu
Myloplus tumukumak
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.
Cardinal Pacu
Cyprinidae
Cardinal shiner
Luxilus cardinalis
Acestrorhamphidae
cardinal tetra
Paracheirodon axelrodi
Poeciliidae
Cardinal toothcarp
Brachyrhaphis roseni
Acestrorhamphidae
Cardinal Toothy
Oligosarcus pintoi
Nemacheilidae
Carian loach
Oxynoemacheilus germencicus
Perciliidae
Carmelita
Percilia gillissi
Cyprinidae
Carmine Shiner
Notropis percobromus
Cyprinidae
Carnatic Carp
Barbodes carnaticus
Poeciliidae
Carnegie's toothcarp
Cnesterodon carnegiei
Percidae
Carolina darter
Etheostoma collis
Percidae
Carolina fantail darter
Etheostoma brevispinum
Ictaluridae
Carolina madtom
Noturus furiosus
Elassomatidae
Carolina pygmy sunfish
Elassoma boehlkei
Cyprinidae
Carp
Enteromius bigornei
Cyprinidae
Carp
Enteromius liberiensis
Cyprinidae
Carp
Labeobarbus parawaldroni
Curimatidae
Carp headstander
Cyphocharax magdalenae
Cyprinidae
Carpathian Barbel
Barbus carpathicus
Petromyzontidae
Carpathian brook lamprey
Eudontomyzon danfordi
Gobionidae
Carpathian gudgeon
Gobio carpathicus
Salmonidae
Carpione del Garda
Salmo carpio
Parodontidae
Carriker's Characin
Parodon carrikeri
Characidae
Carvalho's Tetra
Tetragonopterus carvalhoi
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.