Zoanthids defecating?

[Jaybird]

Not exactly a "what the heck is this" ID question, but an ID question none-the-less. I was watching my zoanthids this morning and noticed that one of them had their mouth open really wide...and then a small dark ball popped out of it and started to float around the tank. I think some of the other ones have done it too.

[roka64]

Probably, they only have one opening.....Food goes in, food goes out....

[quaqa88]

I have seen this in my tank. It is the waste product of the polyp. It is nothing to worry about. Some people even say that it is an egg caused by the asexual reproduction of a polyp.