Animals/Plants‎ > ‎


Symbiosis basically means ‘living together’ and in the context of marine biology refers to a close relationship between two species, for example the Clown fish and the anemone.

These symbiotic interrelationships can be divided into three main categories; Mutualism, when both species involved benefit from the relationship, Commensalism, when one species benefits and the other isn’t affected, and Parasitism, when one species benefits, and the other is harmed in the process.

There is a fourth, less ‘intimate’ category of symbiosis known as Mimicry, which involves one species imitating another to gain the benefits enjoyed by that species. 

For example a Banded snake eel mimicking a venomous sea snake in order to deter predators.

 “Why live together?”

There is always competition for food and territory in the animal world. To avoid competing with other species it is expedient for an animal to find a ‘specific’ niche within their environment. Another way to avoid direct competition is to form a stable relationship with another species, one other than a ‘predator-prey’ relationship. This allows two species to ‘harmoniously’ share the same space and/or a food supply.

Often a fish can be involved in two symbiotic relationships at once; suffering from parasitism on the one hand, and benefiting from mutualistic cleaning attention on the other. Using that example, the saying “one mans rubbish is another mans treasure’, could be changed to read; “one creature’s parasites are another creature’s food!”

Symbiosis is always ‘inter-specific’; that is it occurs only between different species; intra-specific relationships (relationships within a single species) cannot be described as symbiosis.