So I went into Petco and noticed some small snails in their marine tanks. The associate said I could have them for free, but be careful what I wish for because shes had to deal with these in her own tank. She guessed they were little nerite or zebra snails or possibly turbo, but after some brief googling, Im guessing maybe collonista? It looks like there may be more than one type of snail as well. Can someone help me ID these and tell me whether or not Id even want them for free? Theres like 20+ if I want them.