Parodontidae
Bahia Characin
Apareiodon itapicuruensis
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.
Bahia Characin
Salmonidae
Baikal black grayling
Thymallus baicalensis
Salmonidae
Baikal White Grayling
Thymallus brevipinnis
Nemacheilidae
Baishuijiang high-plateau loach
Triplophysa baishuijiangensis
Fundulidae
Baja California Killifish
Fundulus lima
Cyprinidae
Bakır shemaya
Alburnus attalus
Cyprinidae
Bala shark
Balantiocheilos melanopterus
Psilorhynchidae
Balitora minnow
Psilorhynchus balitora
Salmonidae
Balkan Brook Trout
Salmo farioides
Cobitidae
Balkan Loach
Cobitis elongata
Cyprinidae
Balkhash marinka
Schizothorax argentatus
Percidae
Balkhash perch
Perca schrenkii
Acestrorhamphidae
Ball Astyanax
Moenkhausia comma
Percidae
Balon's ruffe
Gymnocephalus baloni
Ictaluridae
Balsas Catfish
Ictalurus balsanus
Astroblepidae
Balsas climbing catfish
Astroblepus labialis
Poeciliidae
Balsas Livebearer
Poeciliopsis balsas
Poeciliidae
Balsas Molly
Poecilia maylandi
Atherinopsidae
Balsas Silverside
Atherinella balsana
Goodeidae
Balsas Splitfin
Ilyodon whitei
Percichthyidae
Balston's pygmy perch
Nannatherina balstoni
Osphronemidae
Balunga Betta
Betta balunga
Cyprinidae
Banarescu’s barb
Capoeta banarescui
Mormyridae
Bandama mormyrid
Mormyrus subundulatus
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.