Heptapteridae
Catfish
Heptapterus mustelinus
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.
Catfish
Loricariidae
Catfish
Hisonotus nigricauda
Loricariidae
Catfish
Hypostomus borellii
Loricariidae
Catfish
Hypostomus commersoni
Loricariidae
Catfish
Hypostomus laplatae
Loricariidae
Catfish
Hypostomus luteomaculatus
Loricariidae
Catfish
Hypostomus micromaculatus
Loricariidae
Catfish
Hypostomus punctatus
Loricariidae
Catfish
Hypostomus regani
Loricariidae
Catfish
Loricaria apeltogaster
Loricariidae
Catfish
Loricariichthys anus
Loricariidae
Catfish
Loricariichthys labialis
Loricariidae
Catfish
Loricariichthys maculatus
Loricariidae
Catfish
Megalancistrus parananus
Pimelodidae
Catfish
Megalonema platanum
Pseudopimelodidae
Catfish
Microglanis cottoides
Loricariidae
Catfish
Otocinclus flexilis
Doradidae
Catfish
Oxydoras kneri
Loricariidae
Catfish
Paraloricaria vetula
Pimelodidae
Catfish
Parapimelodus valenciennis
Heptapteridae
Catfish
Pimelodella chagresi
Pimelodidae
Catfish
Pimelodus albicans
Pimelodidae
Catfish
Pimelodus maculatus
Siluridae
Catfish
Pterocryptis cochinchinensis
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.