Small marine animals such as copepods, crab larvae and tiny fish fry. Its tentacles kill prey with their sting and then move the food to its mouth, which is on the underside of its disc.
It floats freely in the water, and is moved along by ocean currents and wind.
They are hermaphrodites (i.e. both male and female). The specialised reproductive polyps release both eggs and sperm into the water. When the eggs have been fertilised by the sperm, they develop into larvae that subsequently metamorphose into individual polyps. A Blue Button colony forms when one polyp divides to form new types of polyps which become specialised for different functions.