Saturday, 7 March 2020


The colourful wee fellows you see here are Clown Fish. They have an unusual relationship with sea anemones. Clownfish or anemonefish are fishes from the subfamily Amphiprioninae in the family Pomacentridae. Thirty species are recognized: one in the genus Premnas, while the remaining are in the genus Amphiprion.

In the wild, they all form symbiotic mutualisms with sea anemones, each providing benefits to the other.

The individual species are generally highly host-specific, and especially the genera Heteractis and Stichodactyla, and the species Entacmaea quadricolor are frequent anemonefish partners.

The sea anemone protects the anemonefish from predators, as well as providing food through the scraps left from the anemone's meals and occasional dead anemone tentacles, and functions as a safe nest site. In return, the anemonefish defends the anemone from its predators and parasites.

The anemone also picks up nutrients from the anemonefish's excrement. The nitrogen excreted from anemonefish increases the number of algae incorporated into the tissue of their hosts, which aids the anemone in tissue growth and regeneration.

The activity of the anemonefish results in greater water circulation around the sea anemone, and it has been suggested that their bright colouring might lure small fish to the anemone, which then catches them. Studies on anemonefish have found that they alter the flow of water around sea anemone tentacles by certain behaviours and movements such as "wedging" and "switching". Aeration of the host anemone tentacles allows for benefits to the metabolism of both partners, mainly by increasing anemone body size and both anemonefish and anemone respiration.