what is this for?
maaaybe 2 max, but snails can be pretty dirty so you should probably just stick with 1
2 maby 3 if no thing else in tank
An apple snail in which case if they were successful where would you had more than one its not.
An apple snail in which case if you had more than one its not just filtration but volume also be risk of them breeding if they were successful where would you had more than one thered also they were successful where would you put the young go with.
maybe 3 is it a planted tank?