Coral are not completely defenseless against attacking juvenile crown of thorns starfish and can fight back to inflict at times lethal damage, new research has found.

This occurs during a period of the crown of thorns starfish life cycle, where small juveniles shift from a vegetarian diet of algae to coral prey. But this change in diet makes the juveniles more vulnerable to attack by coral.

Population outbreaks of adult crown of thorns starfish, alongside coral bleaching is one of the greatest threats to tropical reef habitats.

Video footage shows when the tube feet (small tube-like projections on the underside of a starfish's arm used for movement) of juvenile crown of thorns starfish reaches out to touch the coral, the entire arm curls back to avoid the corals' defensive stinging cells. To protect themselves, coral polyps have stinging cells in their sweeper tentacles and outer tissue called nematocysts, that are also used to capture food.

This encounter damages the arms of juvenile crown of thorn starfish, delaying their growth into adulthood. Researchers also saw a 10 percent fatality rate among the juvenile crown of thorns starfish they studied. However, most juveniles that survived arm damage were able to regenerate partially lost arms.