The blue streak cleaner wrasse changes sex from female to male- In the wrasse family (Labridae), the largest female of the harem will change into a male and will take over the harem when there is a loss of the dominant male Most Wrasse bury themselves in the sand at night to sleep and can also perform this behaviour when threatened or startled. The batfish plays dead when danger is near- when a batfish feels scared or threatened it floats motionless on its side making it look like a dead leaf floating on the surface of the water.