The crown-of-thorns starfish is protected from many types of predators by its long, venomous spines, though many adults (up to 60% within a population) may have missing arms, indicating that predation does occur. Juveniles assume more cryptic behaviors, inhabiting crevices and the undersides of ledges. Predators of A. planci include the giant triton shell Charonia tritonis and various fishes in the families Balistidae and Tetraodontidae, which have horny plate-like scales and strong sharp teeth that allow them to remove chunks of tissue from A. planci.

Known Predators:

• Giant triton shell, Charonia tritonis
• White-lined pufferfish, Arothron hispidus
• Harlequin shrimp, Hymenocera picta
• Triggerfish, Balistoides viridescens, Pseudobalistes flavimarginatus
• Lined fireworm, Pherecardia striata