would snails be spawning during the cruing process? its only been a couple days since i took the rocks out of the box! But to be honest i dont know too much snails though...
Could be the squirts, the rock just has some basic purple coraline algea with a couple of feather duster worms. The fluid seems to be coming out from inside the rock, ive been right in front of the tank a few times when its happend and cant see and organisms atleast on the surface that could casue this. ill try and get figure out how to post decent sized pictures and take a photo of the rock in question.