Nuisance snails are often a sign of excessive organic matter in the aquarium such as uneaten food, plant remains or detritus. Reviewing feeding regimes and hoovering out debris with a gravel cleaning syphon are often enough to control numbers. For more effective eradication, a number of options are available. Although snail killing chemicals can be purchased, these are often damaging to sensitive fish and can be lethal if dosage rates are not carefully calculated. Snails are often only temporarily controlled and need to be removed by hand after treatment. Although not specifically designed to target them, Discus worming treatments are often toxic to snails and can be used without affecting most species of fish. Other ways of removing snails include catching them with either specially made traps, tablets of fish food placed under an over turned saucer or by placing a well-washed lettuce leaf in the aquarium and removing them by hand.
Less hands-on techniques involve using organisms that eat snails and these include a range of animals. For large aquaria, Clown loaches (Chromobotia macracanthus) can be used but are capable of out-growing most small home aquaria. Their smaller relatives the Zebra loach (Botia striata) and Dwarf Chain loach (Yasuhikotakia sidthimunki) are a much better choice for the smaller aquarium and both enjoy eating snails. Keep these social fishes in small groups. Other snail-eating fish include the nocturnal Talking catfishes and both Spotted (Agamyxis pectinifrons) and Striped (Platydoras costatus) species are available.
For tanks where adding fish is not an option, the Assassin snail (Anentome helena) is a slow but effective means of controlling small snails and ideal for small aquaria. Once the tank is free of snails, the assassins will eat frozen food or meaty sinking pellets.