I can tell you a little about Apple Snails.There are numerous species. From Cana's that get to be almost the size of softballs,and eat Aquarium plants, To Pomacea Bridgesii AKA-"Brig" Snails,who come in a rainbow of color's,grow to golf ball size,and usually only eat dead or rotting plant materials in your tank.Snails need a PH of 7.5---8,in order to keep their shells hard & healthy.Snails do NOT live on algae alone. They will eat bloodworms,shrimp pellets,fish food,and most types of veggies are preferred. Snails need extra calcium .You can do this by placing a cuttlebone,and /or Liquid calcium into the tank daily. SNails need veggies like spinach/Kale/collard greens/zucchinni/etc.in their daily diet. If you have any more questions, etc. Check out
Apple SnailsHope this helps.

P.S. Snails are very sensitive to Most meds in your fish tanks.