You’ll hear different opinions about whether you can use snails or whether you should even allow them in your aquaponics system. In general, there are two schools of thought. The first one is that snails can be genuinely useful in an aquaponics system, acting as a bellwether for feeding issues, a quick processor of excess fish food and other biowaste, and the occasional fish snack. Snails will be quick to consume any excess fish food that sinks to the bottom of your tank, reducing the risk of water quality problems as it decomposes. When there is an abundance of this kind of waste, the snails will quickly multiply. When you see multitudes of snails everywhere you look, that’s a good signal to reduce your feeding. As the food source dries up, the population of snails will fall. When you’ve reached a good equilibrium, you’ll be able to recognize the “right” population and notice when it gets out of whack. Then, of course, some fish types (tilapia, for example) love to enjoy an occasional crunchy snack. If you suddenly notice that your stable population of snails has plummeted, it’s a good time to check to see if you need to consider increasing the daily food rations. If you’re planning to enlist snails for this kind of work, the best species is the Rams Horn snail, since it multiplies quickly when food is plentiful and thus will give you the fastest feedback on feeding issues.
The other school of thought is that snails are a problem and should be avoided whenever possible. Some snails will feed on the roots of your plants and since the water is recirculated throughout the system, it’s hard to contain all snails to just the fish territory. Snails brought in from outside (your local pet store, for example) can introduce parasites or diseases to your system. It is worth noting, too, that once introduced, snails can be virtually possible to eliminate without use of chemicals -- a big no-no in organic operations.
