Life on a whip

For this tiny shrimp of tropical seas , the whip coral is an all-important , life-preserving habitat . Anker ’ s whip coral shrimp , Pontonides ankeri , is barely 2cm long , and has taken on the colour of its host whip coral to help with camouflage . It forms a commensal relationship with the coral , meaning an association between the two in which the shrimp benefits , while the coral derives neither benefit nor harm . In this case , the shrimp gets shelter , a suitable background for its camouflage and a vantage point for catching planktonic food . Females grow to be far larger than males ; when both sexes are full grown , the females are up to three times the size of the males . Instinctively shy , they react to the presence of a diver by shifting to the ‘ invisible ’ side of the whip , making them hard to locate . Photo by Saeed Rashid , focusvisuals . com