Protocooperation: It is a positive interaction in which both the species will be benefited but they can live equally well without this association.
Example: Sea anemone and Hermit crab
The sea anemone (Adamsia) gets attached to the molluscan shell of the hermit crab (Eupagurus). Sea anemone gives protect to the crab and the crab in turn carries the anemone to new feeding grounds.