Rivulidae
Hispaniolan rivulus
Rivulus roloffi
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.
Hispaniolan rivulus
Cyprinidae
Hitch
Lavinia exilicauda
Cichlidae
Hoehne's Dwarf Cichlid
Rondonacara hoehnei
Eleotridae
Hoese’s Gudgeon
Allomogurnda hoesei
Nothobranchiidae
Hofmann's killi
Aphyosemion hofmanni
Callichthyidae
Hognosed brochis
Corydoras multiradiatus
Cyprinidae
Holcik's spirlin
Alburnoides holciki
Poeciliidae
Holdridges toothcarp
Brachyrhaphis holdridgei
Percidae
Holiday darter
Etheostoma brevirostrum
Cyprinidae
Holland's Carp
Spinibarbus hollandi
Serrasalmidae
Holland's Piranha
Serrasalmus hollandi
Terapontidae
Holsworth's grunter
Syncomistes holsworthi
Osphronemidae
honey gourami
Trichogaster chuna
Loricariidae
Honeycomb Pleco
Hypostomus faveolus
Auchenipteridae
Honeycomb Tatia
Duringlanis perugiae
Clariidae
Hong Kong catfish
Clarias fuscus
Osphronemidae
Hong Kong Paradise Fish
Macropodus hongkongensis
Amblyopsidae
Hoosier cavefish
Amblyopsis hoosieri
Cyprinidae
Hora danio
Devario shanensis
Cyprinidae
Hora razorbelly minnow
Salmostoma horai
Cichlidae
Hore's haplo
Shuja horei
Polynemidae
Hornaday's paradise fish
Polynemus hornadayi
Cyprinidae
Hornyhead chub
Nocomis biguttatus
Cyprinidae
Horse Barbel
Barbus fucini
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.