Other creatures in the sea, perhaps. Interspecies grooming is a thing, and "grooming" or at least cleaning is a side benefit from 'parasites' that clean food f

Other creatures in the sea, perhaps. Interspecies grooming is a thing, and "grooming" or at least cleaning is a side benefit from 'parasites' that clean food from predators, including from between their teeth (eg: Docker fish cleaning shark teeth).