Agonidae
bigeye poacher
Bathyagonus pentacanthus
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.
Agonidae
Bathyagonus pentacanthus
Carangidae
Selar crumenophthalmus
Plectrogeniidae
Plectrogenium nanum
Cottidae
Triglops nybelini
Sebastidae
Helicolenus barathri
Platytroctidae
Holtbyrnia macrops
Congridae
Ariosoma megalops
Hexanchidae
Hexanchus nakamurai
Alepocephalidae
Bajacalifornia megalops
Liparidae
Temnocora candida
Lutjanidae
Lutjanus lutjanus
Holocentridae
Ostichthys trachypoma
Tetragonuridae
Tetragonurus atlanticus
Sciaenidae
Stellifer musicki
Dactyloscopidae
Dactyloscopus crossotus
Pempheridae
Pempheris megalops
Alopiidae
Alopias superciliosus
Scombridae
Thunnus obesus
Ogcocephalidae
Dibranchus discors
Macrouridae
Hymenocephalus megalops
Pristigasteridae
Opisthopterus macrops
Parazenidae
Stethopristes eos
Zoarcidae
Lycodes cortezianus
Myctophidae
Symbolophorus californiensis
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.