Those are nerite eggs. I'm trying to breed them in water of SG 1.012. I've tried doing some research, but haven't really found anything conclusive about actually being able to breed these guys. I've read all sorts of different things about slinity changes, different larval stages, etc but it all seems pretty speculative. I'm just leaving them in the tank for now, if nothing comes of it after a month or so I might try some other things to see if they help.