Nothobranchiidae
Blue gularis
Fundulopanchax sjostedti
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.
Blue gularis
Cichlidae
Blue Head Apisto
Apistogramma resticulosa
Cichlidae
Blue Johanni Cichlid
Pseudotropheus cyaneorhabdos
Osphronemidae
Blue Licorice Gourami
Parosphromenus gunawani
Nothobranchiidae
Blue lyretail
Fundulopanchax gardneri
Cyprinidae
Blue Mahseer Barb
Neolissochilus stracheyi
Cichlidae
Blue Mbuna
Labeotropheus fuelleborni
Cyprinidae
blue moon danio
Devario xyrops
Cichlidae
Blue neon cichlid
Paracyprichromis nigripinnis
Nothobranchiidae
Blue notho
Nothobranchius patrizii
Cichlidae
Blue orchid aulonocara
Aulonocara kandeense
Cichlidae
Blue Panda Apisto
Apistogramma panduro
Cichlidae
Blue Peacock Bass
Cichla piquiti
Melanotaeniidae
Blue rainbowfish
Melanotaenia caerulea
Cottidae
Blue Ridge sculpin
Cottus caeruleomentum
Siluridae
Blue Sheatfish
Kryptopterus cryptopterus
Cyprinidae
Blue shiner
Cyprinella caerulea
Osphronemidae
Blue Spot Betta
Betta brownorum
Poeciliidae
Blue spotted Guatamala toothcarp
Pseudoxiphophorus anzuetoi
Cichlidae
Blue spotted tilapia
Oreochromis leucostictus
Cichlidae
Blue Steel Apisto
Apistogramma caetei
Catostomidae
Blue Sucker
Cycleptus elongatus
Stevardiidae
Blue Tetra
Knodus borki
Stevardiidae
Blue tetra
Mimagoniates microlepis
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.