Cichlidae
Humphead cichlid
Cyphotilapia frontosa
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.
Humphead cichlid
Cichlidae
Humphead cichlid
Cyphotilapia gibberosa
Cichlidae
Humphead Dwarf Acara
Laetacara araguaiae
Ambassidae
Humphead Glassfish
Parambassis pulcinella
Cichlidae
Humphead Madagascar cichlid
Katria katria
Cyprinidae
Hyphen barb
Enteromius bifrenatus
Acestrorhamphidae
Hyphessobrycon ulreyi
Hemigrammus ulreyi
Osphronemidae
Ibanorum Betta
Betta ibanorum
Cyprinidae
Iberian Barbel
Luciobarbus bocagei
Cyprinidae
Iberian Barbel
Luciobarbus comizo
Gobionidae
Iberian gudgeon
Gobio lozanoi
Cyprinidae
Iberian nase
Pseudochondrostoma polylepis
Cyprinidae
Iberian-Chub
Squalius pyrenaicus
Cyprinidae
Iberian-Roach
Squalius alburnoides
Parodontidae
Ibiti sucker darter
Apareiodon ibitiensis
Gasterosteidae
Iceland stickleback
Gasterosteus islandicus
Bagridae
Idukki Mystus
Mystus menoni
Cichlidae
Igara Pike Cichlid
Crenicichla igara
Acestrorhamphidae
Iguape Tetra
Deuterodon iguape
Cichlidae
Iguassu Biglip Pike Cichlid
Crenicichla iguassuensis
Pimelodidae
Iguazu Catfish
Steindachneridion melanodermatum
Cyprinidae
Ili marinka
Schizothorax pseudoaksaiensis
Cyprinidae
Illyrian chub
Squalius illyricus
Callichthyidae
Imitator cory
Corydoras imitator
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.