Nemacheilidae
Melid loach
Oxynoemacheilus kaynaki
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.
Melid loach
Cyprinidae
melon barb
Haludaria fasciata
Cyprinidae
Menderes bream
Vimba mirabilis
Cyprinidae
Menderes brook minnow
Pseudophoxinus maeandricus
Cyprinidae
Menderes nase
Chondrostoma meandrense
Cichlidae
Mendezi Dwarf Cichlid
Apistogramma mendezi
Achiridae
Menezes' Sole
Apionichthys menezesi
Acestrorhamphidae
Menezes' Toothy
Oligosarcus menezesi
Bagridae
Menoda catfish
Hemibagrus menoda
Nemacheilidae
Mentum barbel Yunnan loach
Yunnanilus mentibarbatus
Cyprinidae
Merah Dwarf Barb
Boraras merah
Percidae
Meramec Saddled Darter
Etheostoma erythrozonum
Poeciliidae
Merry widow livebearer
Phallichthys amates
Poeciliidae
Meshscaled Topminnow
Lacustricola chobensis
Poeciliidae
Meshscaled topminnow
Lacustricola hutereaui
Nemacheilidae
Mesonoemacheilus petrubanarescui
Nemacheilus petrubanarescui
Cyprinidae
Mesopotamian barb
Capoeta damascina
Cyprinidae
Mesopotamian barb
Capoeta kosswigi
Cyprinidae
Mesopotamian barbel
Luciobarbus subquincunciatus
Cyprinidae
Mesopotamian minnow
Barilius mesopotamicus
Acestrorhamphidae
Meta Tetra
Hyphessobrycon metae
Cyprinidae
Metallic Bitterling
Acheilognathus typus
Poeciliidae
Metallic livebearer
Girardinus metallicus
Cyprinidae
Metallic shiner
Pteronotropis metallicus
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.