Tiger grouper opening his gills for a small Spanish hog fish as an invitation to be checked for parasites (Caribbean).

 

Not only fish clean, but also certain kinds of shrimp. However, shrimp have to be careful they are not eaten themselves, therefore this cleaner shrimp lives in symbiosis with a stinging sea anemone (Caribbean).

 

This Tiger Grouper has noticed the cleaner shrimp in the sea anemone and opens his mouth to get his teeth cleaned (Caribbean).