Mystery snails are small, colourful and fun to watch, but they also serve an important purpose โ which is cleaning the tank! They feed on algae, decaying leaves, and leftover food, helping reduce waste buildup. Their large, smooth shells come in many colors, adding a decorative touch to the tank. Unlike pest snails, they donโt reproduce uncontrollably and are easy to care for. Mystery snails also help aerate the substrate by burrowing lightly, promoting better water circulation at the bottom of the tank.