Anemone Shrimp

Immunity to an anemone is not something these animals are born with. It is something they build, and it takes hours.

A shrimp moving into a new anemone starts by touching it briefly with the tips of its legs and antennae, pulling back, and going in again, over and over, extending the contact each time. What it is doing is accumulating a coat of the anemone's own mucus, and possibly adjusting its own, until the surface it presents no longer reads as prey to the stinging cells. Wash a settled shrimp in clean water for long enough and it loses the protection and has to start again.

So the relationship is maintained rather than given, and an animal separated from its host is in real trouble until it repeats the process.

This is one of the smallest of the anemone shrimp here, two centimeters and near transparent, usually in pairs on a single host. It picks food from the anemone's tentacles and cleans the surface, and it lives on a carpet of stinging cells it renegotiates with continuously.