what size is your tank. The most commonly available snail munchers are too big for that tank.
Take a look through the loaches in the fish index. There might be some info there about which fish would work well for snail extermination.
other methods of snail extraction include
1. the lettuce trick. This involves placing a leaf of lettuce in your tank (preferrably near lights out) then come back an hour later and either remove the lettuce leaf and throw it away, or rinse it well and place it back into the tank to catch more snails. This will not get rid of all the snails and it will not get rid of the snail eggs. I'm a little reluctant to put a lettuce leaf in my tank (pesticides, I know I'm wierd people put veggies in to feed fish all the time) if you are the same you could try another method that IME works very well. It involve placing an algae wafer in a coffee mug and putting it in the tank. come back in an hour or so and rinse out the mug. repeat until lots of snails are gone.
2. chemicals. I don't really like this method since it tends to leave a lot of snail corpses in the water but since you only have a few snails it may be a path you would like to travel, it is pretty straight forward. Add some copper based medication or a commercial snail killer (such as hadasnail) to the water as directed then remove as many snails as you can. that's it
3. pick them out and throw them away whenever you see them
4. learn to live with and enjoy them. as I believe i said earlier they are helpful when it comes to feeding in moderation.
5. get a snail eating fish such as a dwarf puffer (probably too aggressive for your tank) or a clown loach (probably to large for your tank) I'm sure someone else can help you figure out what fish would work well.
