help with snails

[hood]

Hello all, I've had my tank for about three weeks and everything was going great. Then one day I look and all my snails were acting funny. (They were sitting upside down scrunched up.) Now their not even there anymore. They imploded. I had six, and now I have two. Weird thing is the ones that died were all my big ones and not the small ones. The little ones are still goin. The pet store guy told me he'd never heard of anything like that. Any idea of what it could be?

[seabass]

What are your water parameters (temperature, salinity, ammonia, nitrites, and nitrates)? What type of water are you using (tap, RO, RO/DI, distilled, or NSW)? Is their any chance that there were ever any copper meds used in your tank?

 

Do you have any crabs that might be trying to eat them? Also, most snails can’t right themselves when the fall on their backs; they need you to turn them over.