FISH ATLASGLOBAL FISH ENCYCLOPEDIA

FISH SPECIES

Saltwater Fish

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.

FISH ATLAS / FIELD GUIDESaltwater FishIN THIS CHAPTER01 / Characteristics02 / Lifestyle03 / Species04 / Field notes
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01 / NATURAL HISTORY

Characteristics

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.

  • 01Osmoregulation in saline waters
  • 02Hydrodynamic & camouflaged forms
  • 03Complex marine trophic partitioning
Rathbunella hypoplecta 的物种图片
Marine Fish

02 / LIFESTYLE

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

  1. Pelagic schooling coordination
  2. Reef and crevice sheltering
  3. Tidal and photic activity shifts

03 / SPECIES

Representative species

View all species

Discover representative species illustrating the ecological diversity, morphologies and adaptations of this group.

Labridae

Thalassoma bifasciatum 的物种图片

bluehead

Thalassoma bifasciatum

04 / FIELD NOTES

A closer look

Do saltwater fish drink water?

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.

Do all saltwater fish live on reefs?

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.

Can a species live in both freshwater and saltwater?

Yes. Euryhaline and migratory species like salmon, bull sharks and European eels actively adjust their osmotic regulation between fresh and marine waters.