Are these snails tiny, and cone like, with hard shells.


Or more circular with more easily crushable shells.


The later of the 2 are easily crushed on the glass, and in many cases will be eaten by cory's and angels.
The cone snails are a bit hard to crush, but can be baited, and when the bait is covered in snails early in the morning, pulled out and disposed of.
They can also be vacuumed out during water changes, and a glut of them usually means more vacuumimg of left over food would be a good idea.
During the day these cone snails usually bury them selves in the substrate. I find this habit a positive thing, because it keeps the substrate pliable, and slightly aerated, so in this way, it doesn't go anoxic.
Adding snail eating fish, to such a small tank, may be problematic.