Snails are a popular tank addition for the freshwater aquarist, and come in a variety of colors and sizes. Just as varied is how they can affect your freshwater tank. Some snails prefer to eat live plants, and others prefer to eat other snails! Caution should be taken before adding any of these gastropods to your tank.
Benefits of the Assassin Snail
The assassin snail, much like its name indicates, preys upon other snails in your freshwater tank. This omnivorous mollusk is harmless to fish and shrimp, but will help control snail overpopulation in your tank. Live plant enthusiasts find the short work of the assassin snail a boon to the microscopic snail eggs residing on newly purchased greenery. When the snails begin to grow and eat live plants in the tank, the assassin snail simply steps in and handles the infestation.
Negatives of the Assassin Snail
Not all snails eat live plants, and many thrive peacefully on algae, fish waste and fallen leftover fish food. Unfortunately, the assassin snail takes hit orders from no man, and will not differentiate between benign snails that clean the tank and those that prefer to chomp on your nice, new living plants. A hungry assassin snail also will go after "wigglers," i.e. immobile fish fry, which can be a negative for those breeding their freshwater fish.
Benefits of the Trumpet Snail
The Malaysian trumpet snail (MTS) feeds mostly on detritus and algae, and is a boon for aquarists who stock messy freshwater fish, such as goldfish or other carp. The MTS also will aerate substrate as it burrows beneath it searching for leftover food and fish waste. This helps aquarists who keep live plants, as it promotes root growth and additional air exchange. The trumpet snail comes in a wide array of colors and patterns, providing an aesthetic element to your freshwater tank.
Negatives of the Trumpet Snail
The trumpet snail reproduces very rapidly in conducive environments, and unsuspecting aquarists have been surprised by an explosion of baby trumpet snails suddenly cruising their tanks. The MTS' ability to procreate is to such an extent that it holds a reputation as a pest snail, despite not eating live plants or other snails. Chemicals, loaches, assassin snails and manual removal are the best ways to combat a sudden infestation. Trumpet snails also are notorious for hiding in store-bought live plants, leading to an unplanned introduction of the species to a tank.