One of the standard shark images that have become familiar to us show the animal surrounded by a school of small, black and white striped pilot fish. In the past it was thought that these hangers on 'assisted' the shark in some way, for instance 'guiding' it towards potential food.
Recent evidence suggests nothing of the sort.
Occasionally a shark will be observed snapping at its unwelcome guests, but these are usually too wary and agile to be caught. However, if a shark feels itself to be excessively plagued by pilot fish, it will eventually reach a remarkable solution. What happens is that afflicted shark A approaches contented shark B that has the good fortune to be free of these hitch hikers.