Suohhen
Well-Known Member
The picture and description does nothing for me. All I can see is that the polyps around this spot are closed so it could certainly be something is irritating the coral but it could also be that the closed polyps have drawn your attention. How long have you had this coral? Does this thing move around and what is it's base color? Looks purple like the color of stolon to me.
Suohhen
Well-Known Member
It could certainly be a mushroom. If it is usually not visible that is some indication that it is losing the fight for territory with the zoas. They come from the same environment so it isn't distypical for them to embed in with zoa and generally the only way it could harm the zoa would be to overshadow it.
Ofc this is just a guess as to what it is but if you'd like to confirm you should be able to pry it off with a fingernail as it won't be able to get too good of a grip on the stolon.
If it is a mushroom and you wish to keep it you can stick it in a calm spot on rock or if there isn't a good spot where it won't blow away you can put some coral rubble in a basket and it will grab on then you can glue that rubble wherever you'd like it. Usually even a grain of sand will work as it is the slime of the mushroom which makes it impossible to glue onto.
