Cleaner shrimp is a generic term for any swimming decapod crustacean that cleans other organisms of parasites. This is a widely-cited example of symbiosis: a relationship in which both parties benefit. The fish benefit by having parasites removed from them, and the shrimp gain the nutritional value of the parasites. In many coral reefs, cleaner shrimp congregate at cleaning stations.

Scavenger; cleaner of parasites off fishes.

sources: Wikipedia and Julian Sprung Invertebrates A Quick Reference Guide
Purple