In order for an animal to be considered eusocial, it must satisfy the three criteria defined by E. O. Wilson.
Synalpheus regalis, a eusocial shrimp, also is an example of an organism that seeks to increase its inclusive fitness.
Synalpheus regalis is a eusocial shrimp that protects juveniles in the colony.
Some species are nearly eusocial, lacking only a specialized caste system and a queen.