Perfect, so my online guessing could be right. So I assume not a bad thing, just looked strange it slowly taking over. As for the vermetid snails, that's another challage, I think I failed removing them manually the first time, just ended up with moreWelcome to R2R!
Looks like sponge growth and some vermetid snails
This is clatharina sponge which can be invasive in time. Can be pulled off with a dental pick or similarHi there, I have my very first question to ask on here. I have here a photo of a bit of rock, that appears to be growing this white stuff on, kind of looks like under water mould when I tried to research online closest I could come up with was some kind of sponge. Basically wanting to know what it is and is it harmfull. Many thanks Henry
