They are very very pointy and hard to remove. I've tried to take them off plumbing and they require some good force to move. Also very sharp almost cut my hand a few times when cleaning out skimmer head and didnt realize they where there.
Hmmm probably I didn't think they were put I took one out and it looks defiantly like one! Thanks... now I just need to know if its a keyhole..(My zoa population is defiantly not growing at all mostly dying slowly might be a lighting issue, other corals seem fine though)
Just regular ones im guessing? Would they grow without the hole in the top of the shell when they are smaller, and then eventually get it?(sorry for all the questions)