In marine habitats, a number of small creatures are involved in a “cleaning
symbiosis.” At least six species of small shrimp, frequently brightly colored, crawl over
fish, picking off parasites and cleaning injured areas. This is not an accidental
occurrence, because fish are observed to congregate around these shrimp and stay
motionless while being inspected. Several species of small fish (wrasses) are also
cleaners, nearly all of them having appropriate adaptations such as long snouts,
tweezer-like teeth, and bright coloration. Conspicuous coloration probably
communicates that these animals are not prey.