Nothobranchiidae
Korthaus’ killifish
Nothobranchius korthausae
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.
Korthaus’ killifish
Galaxiidae
Kosciuszko Galaxias
Galaxias supremus
Cottidae
Koshewnikow's Sculpin
Cottus koshewnikowi
Sisoridae
Koshi Nangra
Nangra assamensis
Sisoridae
Kosi nangra
Nangra nangra
Salmonidae
Kosogol grayling
Thymallus nigrescens
Cyprinidae
Kosswig’s barb
Carasobarbus kosswigi
Nemacheilidae
Kosswig’s loach
Turcinoemacheilus kosswigi
Cichlidae
Kotsovato
Paretroplus kieneri
Osphronemidae
Krabi mouth brooder betta
Betta simplex
Nemacheilidae
Krajom Mountain loach
Magnischistura khaokrajom
Cichlidae
Krauss' Basketmouth
Caquetaia kraussii
Cyprinidae
Krbava minnow
Delminichthys krbavensis
Profundulidae
Kreiser’s Killifish
Profundulus kreiseri
Cichlidae
Kribensis Cichlid
Pelvicachromis kribensis
Nothobranchiidae
Kribi killi
Fundulopanchax fallax
Characidae
Krieg's Mini Tetra
Serrapinnus kriegi
Cyprinidae
Krishna Carp
Hypselobarbus dobsoni
Bagridae
Krishna mystus
Hemibagrus maydelli
Cichlidae
Krobia
Krobia guianensis
Cyprinidae
Krom Redfin
Pseudobarbus senticeps
Loricariidae
Krone's flat suckermouth catfish
Harttia kronei
Nemacheilidae
Krynicki's loach
Oxynoemacheilus merga
Gobionidae
Kuban gudgeon
Gobio kubanicus
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.