Pond Snails

Used in: Animals Two by Two, Environments, Populations and Ecosystems

Pond snail - Nerites sp., Physa, sp.

Ramshorn snail - Planorbis sp.

Background. Many kinds of aquatic snails make excellent additions to an aquarium. All snails have spiral shells that get bigger toward the opening as the snail grows. The snail secretes new shell around the opening and moves in, abandoning the narrow reaches at the tip of the spiral in which it lived as a youth.

The muscular part of the snail that protrudes from the shell is the foot. Its mouth is on the foot right where a human’s foot has a couple of toes. Because of this interesting structure, snails are called gastropods, which means stomach (gastro) foot (pod). The snail scrapes algae from the surfaces over which it travels. A few snails in your aquarium will graze on the algae that grows on the sides and make it possible to see what’s going on inside.

Snails lay gelatinous globs of nearly transparent eggs. These may be stuck to plant material or the sides of the aquarium. After a couple of weeks, they will hatch, and the tiny larvae will swim freely around the aquarium. Soon they begin to grow a shell, which weighs them down and makes them pedestrian. You may find your aquarium swarming with tiny snails. Snails are quite cooperative about providing opportunities to observe their life cycle.

What to do when they arrive. Immediately upon arrival, open bag and place the bag in a cup or similar upright container to prevent tipping. Rinse snails with dechlorinated or spring water prior to transferring to aquarium. Snails will feed on algae or decaying plant matter naturally found in the aquarium. Feed them a bit of flake fish food the first few days.

How to care for them. Aquatic snails are very easy to care for. All you need is a container of aged or chemically dechlorinated (conditioned) water. Keep plenty of aquatic plants in the aquarium for them to eat and to lay their eggs on. Water snails will also eat lettuce, spinach, and zucchini, or fish-feeding cakes and tiny bits of flake fish food. If the snails are in your fish aquariums just add a bit more fish food when you feed your fish. Although water snails eat waste materials and algae, thus helping to keep the aquarium looking clean, it is best to add fresh water once a week to keep them healthy. Be sure to use conditioned water.

What to do with them when the investigations are completed. You can keep the snails in an aquarium with fish or in their own aquarium. A jar or other clear container will work fine. They require very little attention—just maintain the water level and add a bit of food every other day. Give snails to another teacher conducting the module or return to the district science coordinator for distribution to other schools.

Care for the environment. Aquatic snails obtained from pet stores or biological supply houses should never be released into the wild. Snails can become unwanted pests, damaging the environment, local organisms, and food webs. Only snails that have been collected from a local pond or lake can be returned to that same location. Check with local park and wildlife organizations about collecting and returning aquatic organisms.