The wrasse then begins to gorge itself on parasites that it picks from the bodies of the large fish.

• 这种互利合伙关系已发展到：当濑鱼接近到鳍科鱼鳃盖时，鳍科鱼便会张开鳃盖使濑鱼更容易进入下面的细软的呼吸器官。