“As a fish approaches, the shrimp waves its antennae back and forth to attract attention. If interested, the fish swims over and allows the shrimp to climb aboard. The shrimp moves rapidly over the fish, picking off parasites, investigating irregularities, and cleaning injured areas.  As the fish lies quietly, as if in a state of suspended animation, the shrimp is even allowed to make minor incisions to extradite subcutaneous parasites.”