The main reason that causes the appearance of surplus number of snails in a tank is overfeed of tank fishes. The snails feed on fishes meals leftovers and their number grows exponentially. If they have become a problem in a tank, first check if the fishes aren’t overfed. Usually the leftovers accumulate in the tank substrate and become feed storage for snails, therefore the second task is to siphonate the substrate and remove them. Also snails feed on algae and if you don’t have Ancistrus or other alike catfishes in your tank, it’s worth to put them into it to create nutritive competing conditions. Besides, catfishes feed on snail’s eggs.
CHEMICAL APPROACH - It is more often used by beginners due to its seeming simplicity. Chemicals that kill snails should be harmless to other tank inhabitants, but experienced aquarists will tell you that this approach can be used only if you don’t care if other tank inhabitants will survive. Especially if in a tank you have prawns which are very sensitive to such chemical substances, since usually they contain copper that is poisonous to all spineless species. Try not to overdose the chemical substance, since it can be lethal to all your tank. For example, you can use TROPICAL Hydra-Tox.
MANUAL REMOVING OF SNAILS - This is the most tiring and exhausting approach. But the majority of aquarists still use it. Usually, it’s done when cleaning the tank and the snails are removed, too. Though, this isn’t the way to get rid of snails completely, but it helps to control their population.
VEGETABLE BAIT FOR SNAILS - Snails love vegetables such as lettuce, cucumber or cabbage. Pieces of these vegetables can be used as a bait. In the evening put some vegetables on the plate on the tank bottom, in the morning you’ll see a number of snails there and you can remove them from the tank.
Another one way that guaranteedly will help you to get rid of snails is: Take a banana. Put its skin into some warm place for several hours. When the skin gets dark, put it into the tank (better in the evening) and turn the lights of. In the morning you’ll see a number of shellfish on the banana skin. You’ll have to just throw them away If you do this about 3-4 times, you’ll take quite a lot of snails out of the tank. The only drawback of such an approach is that the water gets a bit muddy (it becomes chalky), but it’s ok, it’ll pass in 2-3 days.