Gobiidae
Biwa Goby
Gymnogobius isaza
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.
Biwa Goby
Gobionidae
Biwa Gudgeon
Biwia zezera
Gobionidae
Biwa Moroko Gudgeon
Gnathopogon caerulescens
Siluridae
Biwa Rock Catfish
Silurus lithophilus
Salmonidae
Biwa Trout
Oncorhynchus biwaensis
Gobiidae
Biwayoshinobori Goby
Rhinogobius biwaensis
Cichlidae
Black acara
Cichlasoma bimaculatum
Cyprinidae
Black Amur bream
Megalobrama mantschuricus
Cyprinidae
Black Amur Bream
Megalobrama terminalis
Osteoglossidae
Black arowana
Osteoglossum ferreirai
Callichthyidae
Black band catfish
Corydoras zygatus
Terapontidae
black bream
Hephaestus fuliginosus
Catostomidae
Black buffalo
Ictiobus niger
Ictaluridae
black bullhead
Ameiurus melas
Adrianichthyidae
Black buntingi
Oryzias nigrimas
Auchenipteridae
Black catfish
Trachycorystes trachycorystes
Acestrorhamphidae
Black Caudal Peduncle Tetra
Moenkhausia cotinho
Cichlidae
Black Chin Apisto
Apistogramma allpahuayo
Centrarchidae
black crappie
Pomoxis nigromaculatus
Sciaenidae
black curbinata
Plagioscion auratus
Cichlidae
Black Devil Cichlid
Amphilophus sagittae
Osphronemidae
Black Dwarf Betta
Betta persephone
Alestidae
Black fin moon tetra
Bathyaethiops atercrinis
Cyprinidae
black fish
Carassioides acuminatus
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.