Mollies and Sea Shells

[JP457]

I have 2 mollies in a 5 gallon and I found some shells that I collected a while ago. Could I put them in the tank? They look like gigantic snail shells.

[wetmanNY]

With mollies, sure. The more calcium and carbonate in the water, the better for Mollies.

This is not generally true in freshwater aquaria.