A coleman shrimp, Periclimenes colemani, at their home on a fire urchin, Asthenosoma varians. the shrimp finds protection among the urchin thorns. Note that the
area where the coleman shrimp is located does not have thorns, because it cuts some thorns to make a nest where it resides. a good part of the shrimp’s diet consists of the urchin small tentacles. the urchin, on
the other hand, does not seem to be bothered with this parasitic relationship imposed by the shrimp.