I breed apple snails, LOL. They CAN be good tank mates for bettas, but it really depends on the fish's personality. The fish eating them isn't really much of a worry, but they can, and many will, nip at the snail's body and tentacles until they close up into their shells and are afraid to come out again! They can starve to death, or die of simple stress. Both of my male bettas are fine with the snails (they're a great place for a nap!) Just keep a close eye on them, and feed the snails well. They'll clean up extra fish food, but most won't really touch algae.