|Epifauna | Epifaunal tiering | Epiflora | Infauna | Infaunal tiering | Nekto-benthos | Semi-infaunal | Sessile benthos | Vagile benthos|
Infauna are heterotrophic, benthic aquatic organisms (animals or protists) that live for some or all of their life cycle buried in or burrowed under the sediments, mud, sand, etc at the bottom of the water. They may remain mostly in one place (e.g. bivalves), or they may burrow or explore widely under the sediments in search of food (e.g. some gastropods, crustraceans, etc).
Infauna are common in both the sublittoral and deeper benthic zones.