Hello. I have bought two Nerite Snails from Petco. I have a black one and I guess this white one? When the worker pulled it out she said it has a weird shell, after further looking at the snail, it kind of worries me. As you can see in this photo, it looks to be a huge rock mass growing on the snail? It moves around fine, it’s eating, but I’m very curious to know what it’s on it? It looks to be maybe a brown/gold color originally.