Hemiodontidae
Halfline hemiodus
Hemiodus semitaeniatus
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.
Halfline hemiodus
Anostomidae
Halfline leporinus
Leporinus nigrotaeniatus
Percidae
Halloween Darter
Percina crypta
Cyprinidae
Hamilton's barb
Enteromius afrohamiltoni
Cyprinidae
Hamilton's barila
Opsarius bendelisis
Cyprinidae
Hampala barb
Hampala macrolepidota
Cyprinidae
Hangang Bitterling
Rhodeus pseudosericeus
Nothobranchiidae
Hannelore's killi
Aphyosemion hanneloreae
Cichlidae
Haplochromis borleyi redfin
Copadichromis borleyi
Cichlidae
Haplochromis quads
Copadichromis mbenjii
Cichlidae
Happy
Copadichromis azureus
Cichlidae
Happy
Copadichromis chrysonotus
Cichlidae
Happy
Copadichromis cyaneus
Cichlidae
Happy
Copadichromis jacksoni
Cichlidae
Happy
Copadichromis mloto
Cichlidae
Happy
Copadichromis pleurostigma
Cichlidae
Happy
Copadichromis pleurostigmoides
Cichlidae
Happy
Copadichromis quadrimaculatus
Cichlidae
Happy
Copadichromis verduyni
Cichlidae
Happy
Corematodus shiranus
Cichlidae
Happy
Corematodus taeniatus
Cichlidae
Happy
Mchenga conophoros
Cichlidae
Happy
Mylochromis anaphyrmus
Cichlidae
Happy
Mylochromis epichorialis
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.