Hi Family, newbie here. Just saw these growths on one coral rock, and am not sure what they are, and what I should do about them. Any advice is appreciated!
I'm going to guess sponge. I've seen quite a few random things growing under my rocks over the years and nothing has ever actually been bad for the talk. Don't get me wrong, I've had plenty of bad things growing on TOP of the rocks but nothing so far on the bottom.
Sponges. Only sponge you really gotta watch for is the entrusting grey/purple stuff. Even then it usually just stays in thr darker area but it'll spread fast and everywhere that is dark.