Epibiont

An epibiont is an organism that lives on the surface of another living organism. An epibiont is usually considered harmless to the host; in this sense, the relationship between the two organisms can be considered neutralistic or commensalistic. Typical epibionts are barnacles, remoras and algae, all of which live on many larger marine organisms, such as whales, sharks, sea turtles and mangroves. The host of the epibiont is typically referred to as the basibiont.