The sera snail collect is excellently suited for reducing strongly multiplying snails in aquariums. Snails are lured into the trap by some bait (e.g. sera O-nip tablets). Their way back is blocked by pins. The undesired catching of fish is prevented by pins in the entry of the trap. The sera snail collect can alternatively be used for catching bristle worms in marine aquariums.
More information about the sera snail collect here