Small dangerous needles of fire coral
The fire coral defends itself by tiny poisonous needles, like stinging nettle does. The first time when I touched the coral our guide wet my burns by specially prepared vinegar. Not sure it is the best means. The pain in the burn lasted a week yet and was seen some months. I didn't touch the coral later although I took photos of fish near such coral many times. I think the fish don't touch the coral too. If they do the tiny needles were broken.