The Fire Coral (Millepora alcicornis) is one such animal that isn’t as commonly kept in our aquariums. There are good reasons for this the biggest being that “skin contact with fire coral will result in immediate burning pain, followed by an itchy welt that can last for several days.” That in itself is a great deterrent for hobbyists to keep them in their tanks. However that doesn’t stop Coralmorphlogic from capturing it on video, HD video that is. As the Fire Coral is a resident down in Florida and the guys at CoralMorphlogic, but what causes that painful sting?
Upon close inspection of fire coral, the stinging polyps can be seen as needle-like projections. At even closer magnification, grape-like bunches of stinging nematocysts can been seen protruding along the polyps’ length. These polyps are retractable, and when an edible food particle is captured, it can be drawn back towards one of the many mouths that dot the surface of the colony. In the video we see a colony of barnacle shells (Balanus sp.) that have been encrusted by fire coral. Unlike the corals though, the barnacle can continue to live beneath the veneer of fire coral.
The Fire Coral looks innocent in the video and for the most part it is, as long as you don’t touch it. I can speak from first hand experience that the “burning” sensation that was described above isn’t fun and another reason why I love vinegar.