One often hears that there are real snail plagues in an aquarium. In most cases, these water snails are bubble snails or Malayan trumpet snails, which are often not used consciously, but are brought in with water plants. Also post horn snails and disc snails are often brought into the aquarium unintentionally.
If these snails find a lot of food, they multiply strongly. It is always better to feed as adapted as possible, so that the stock in the aquarium eats the fish food or shrimp food from the can within a few minutes. Fresh food should also never be left in the aquarium for more than a few hours.
However, there are now aquariums where little feeding does not work. Young fish should be in the food, so there must also be a lot of food. Then, of course, residual feeders such as snails are useful, because they prevent the remaining food from rotting and driving the water values into the basement, but sometimes you do want to contain a heavy snail population a little.
Even if you already have a snail plague in the aquarium and then adjust the amount of food, there are still too many snails. Accompanying a reduction of food you should collect snails and give them away (please never, never put them out or flush them down the toilet). Functional animals such as predatory snails or puffer fish are not really suitable for snail reduction - at some point the snails will be gone and the functional animals will continue to need their food.
Simple and convenient is the collection of bubble snails, post horn snails, trumpet snails or Nöppis with a snail trap. The trap is equipped with a food bait and placed in the aquarium. Due to its special construction, it is almost impossible for fish to get caught in the trap.
Even if you breed food snails in an extra aquarium for snails, for example for axolotl, predatory snails, turtles or puffer fish, a snail trap is not wrong for collecting, it saves a lot of work, effort and wet arms.