From the Greek hals - salt and bion - living.

Hydrobionts inhabiting water bodies with salinity above 45%. Typical hydrobionts are: crayfish Artemia salina, alga Dunaliella salina, rotifer Brahionus mulleri, etc.

Hydrobiote (Latin Hydrobiontes; from Ancient Greek ὕδωρ - water + biont) is an organism adapted to living in an aquatic environment (biotope). Hydrobionts (aquatic organisms) are, for example, fishes, coelenterates (sponges, shooters), echinoderms, most crustaceans and mollusks.

The totality of organisms living in the aquatic environment is called hydrobiota.