Snails can bring harm and benefit to the aquarium ecosystem. It all depends on their variety and quantity. Very popular among aquarists are the following species of mollusks as ampulyarii, horn coil, agrolux, Melania. If you in a proper way take care of an aquarium and control the number of snails, they will bring a lot of benefits. Clams are a wonderful aquarium sanitation. They not only eat up food that did not eat fish, but also their excrement. Thus, these aquarium inhabitants contribute to water purification. Uneaten food are favorable environment for growth of pathogenic bacteria, which can in a matter of hours to make clear water muddy. In addition, the shellfish eat dead parts of plants and well scraped his rough tongue bacterial plaque from the walls. This affects the installation of the favorable climate and biological balance in the aquarium. Certain types of shellfish, for example, ampulyarii, serve as the indicator of condition of aquarium water. By their behavior you can determine if there is enough oxygen in the water. When it is insufficient, and at sharp change of pH water ampulyarii up the glass to the surface of the water and pulls his pipe siphon – body, which allows it to breathe air. In this way snail "signals" inexperienced aquarist, it's time to do a water change or buy a good aerator. One of the downsides decorative snails is their active reproduction. A large number of mollusks in the aquarium can lead to overcrowding and, as a consequence, the lack of oxygen at the other inhabitants. In addition, a large population of snails are able to eat off the plants. Optimum can be considered the ratio of one snail per 10 litres of water. Therefore, timely scrape their eggs off the glass, they lay consistently, to prevent the overcrowding of the aquarium.Will inhabit your aquarium snails, or not – to solve only to you. But remember that you can not place shellfish from water bodies, because with them can get infected. In addition, some pond snails secrete mucus into the water, which it contaminates. Get the clams for your aquarium only in pet stores.