I agree with the choice of the Assassin snails. They do not breed like rabbits and when they do reproduce are very slow to grow.
A lot of people here aren't going to want to hear this but overfeeding isn't always the cause of a good pond snail population. I have kept cuttings from aquarium plants in rubbermaid containers under plant lights for weeks. Obviously no food is added to this containers and I change the water about once a week. The snails continue to thrive as long as there is decaying vegetation. If you keep plants like hornwort, wisteria, or java fern which will from time to time have decaying parts of the plant, you will have pond snails.
A lot of people here aren't going to want to hear this but overfeeding isn't always the cause of a good pond snail population. I have kept cuttings from aquarium plants in rubbermaid containers under plant lights for weeks. Obviously no food is added to this containers and I change the water about once a week. The snails continue to thrive as long as there is decaying vegetation. If you keep plants like hornwort, wisteria, or java fern which will from time to time have decaying parts of the plant, you will have pond snails.
