Alepocephalidae
Agassiz' smooth-head
Leptochilichthys agassizii
FISH SPECIES
Saltwater fish, also called marine fish, live in seas and oceans. They range from small reef residents to fast open-ocean swimmers and species that stay close to the seabed.
01 / NATURAL HISTORY
Marine fish regulate water and salts in a very different environment from freshwater fish. Body form often reflects where they live: streamlined swimmers cross open water, while compressed or camouflaged species maneuver around complex habitats.
02 / LIFESTYLE
Marine fish occupy a vast, three-dimensional environment with shifting currents, light gradients and depths. Open-water pelagic species often school to travel efficiently and confuse predators, while reef residents navigate complex crevices between foraging patches. Along the coast and continental shelves, tidal cycles and changing sunlight dictate daily peaks of activity and shelter seeking.
OBSERVATION INDEX
03 / SPECIES
Discover representative species illustrating the ecological diversity, morphologies and adaptations of this group.
Alepocephalidae
Leptochilichthys agassizii
Alepocephalidae
Alepocephalus agassizii
Ophidiidae
Monomitopus agassizii
Labridae
Sparisoma frondosum
Liparidae
Liparis agassizii
Pomacentridae
Pycnochromis agilis
Arhynchobatidae
Bathyraja aguja
Notosudidae
Scopelosaurus ahlstromi
Moridae
Auchenoceros punctatus
Gobiidae
Exyrias akihito
Holocentridae
Ostichthys alamai
Zoarcidae
Bentartia pusillum
Zoarcidae
Bothrocara pusillum
Pleuronectidae
Pleuronectes quadrituberculatus
Rajidae
Arctoraja parmifera
Liparidae
Careproctus colletti
Bathymasteridae
Bathymaster caeruleofasciatus
Cottidae
Triglops metopias
Myxinidae
Eptatretus alastairi
Scombridae
Thunnus alalunga
Halosauridae
Halosaurus radiatus
Anthiadidae
Pelontrus alcocki
Pleuronectidae
Poecilopsetta praelonga
Synanceiidae
Minous inermis
04 / FIELD NOTES
Yes. Because surrounding seawater is saltier than their internal fluids, marine bony fish constantly lose water by osmosis, requiring them to drink seawater continuously and pump excess salts out via gill cells.
No. Coral reefs represent only a fraction of marine environments; the vast majority of marine species inhabit open pelagic waters, continental shelves, or the deep ocean floor.
Yes. Euryhaline and migratory species like salmon, bull sharks and European eels actively adjust their osmotic regulation between fresh and marine waters.