Horn Corals of the Genus Hydnophora are a relatively hardy small polyp stony coral (SPS). They have a very powerful sting and we highly recommend giving it plenty of space. If a colony comes in contact with another SPS, it is very likely that the Hydnophora is going to win and kill off what it touches. Hydnophora have small mouths called hydnophores but has the ability to capture medium-sized food particles. This SPS feeds more aggressively than most and will happily consume small pieces of shrimp and other frozen foods.