Aquatic animals

thumb|upright=1.8| Zooplankton sample including several species of copepods (1–5), [[gastropod larva (6) doliolids (7), fish eggs (8), and decapod larva (9) (Photo by Iole Di Capua)]]

animals that partially or wholly inhabit aquatic habitats

organism that eats the mud at the bottom of bodies of water

A rheophile is an animal that prefers to live in fast-moving water.

Armillifera parva is a species of Ediacaran proarticulate first described by Mikhail Fedonkin in 1980. Its fossils were discovered in the White Sea area, Arkhangelsk Region, Russia. These fossils of A. parva were restricted to almost the same stratigraphic range as Kimberella, although fossils of both organisms have been rarely found.