Hey guys so do snails bred for food actually need calcium? I some pond snails and ramshorn snails in a 20 gallon planted tank. There is a lot of algea in there they can eat as well as fish food that is left over. The tank is also home to a 2-2.5inch Serra Rhom. I was not sure if the snails needed calcium blocks or something like that in there or not. I would prefer not to, because I was concerned it may buffer the water hardness or leach something that would be bad for the piranha. Is it ok if I do not give them calcium, or do they need it?