Cleaning
The residents of the muck also sometimes need to get a bath and the ocean has some really clever ways to keep fish clean of parasites and dead scales: They enlist the help of other muck dwellers. Cleaner wrasses and shrimps step up to the task of keeping their neighbours clean, sometimes even climbing into the mouth of their otherwise predator for a visit from the dentist. Cleaning time is not feeding time though and those requesting spa services will not eat their practitioners. I watched a wrasse scurry over a lizardfish, picking it clean of parasites and the lizardfish stayed completely still, letting the wrasse do its work.