THE OLIVE NERITE, NERITINA RECLIVATA
A Great Algae Eating Snail
by Mike Hellweg
The Olive Nerite is an interesting and useful little addition to the work crew of any planted aquarium. These Florida natives do and fantastic job of cleaning up many different types of algae. They slowly and deliberately cover every square inch of the tank, including every leaf of every plant, eating the algae but not harming the plant itself. In addition, many have exquisite black patterns on their olive brown shells. The pattern on each shell is unique, like the human fingerprint.
Neritina reclivata is the only member of the giant Gastropod family Neritina is regularly occur in fresh water. They bare an amazingly adaptable animal, found in fresh, brackish and marine waters all over Florida and other parts of the Caribbean. Several populations have adapted completely to fresh water, while others move back and forth. Some imported for the aquarium trade even have barnacles attached to their shells! Amazingly, even the barnacles seem to do well enough in fresh water, provided there is enough plankton matter. I have seen the barnacles feeding on baby brine shrimp as the snails crawl over every surface of the tank. This shows that that particular specimen has spent at least some time in a marine environment. That it does well in a fresh water tanks proves their hardiness.
Olive Nerites are relatively small snails, reaching a maximum size of about 1" in diameter. They grow slowly and reproduce slowly as well. Unlike many of the more commonly available aquarium snails that are hermaphrodites, Olive Nerites have separate sexes. Eggs are fertilized internally, and the female lays individual whitish-colored eggs bundles as she grazes along. Although fish seem uninterested in the egg bundles, the adult snails eat the majority of them. A few do hatch into the plankton larval stage, but there are not enough plankton nutrients in out relatively clean aquaria for them to survive to settlement. I have had a few develop into small snails in a greenwater/infusoria tank and outdoors in tubs during the summer months. The small snails grow very slowly. Apparently hard water is beneficial for successful reproduction, since in soft water infusoria tanks, eggs appear but I have not seen any young snails, although the adults seem to adapt fairly well is slowly acclimated to softer water. Like most snails, the young require calcium for their shells to grow properly.
Like any other aquatic animal, they should be slowly adapted to the local water conditions, not just plopped into their new home. When the snails come home, put them in a small container, set up a small drip line, at one drop per second or so, to bring the water from the quarantine tank ( you do use one, don't you?) to their container. When the container is nearly full and the snails have climbed up on the container sides, dump out the water and remove the snails carefully by hand. Add them gently to the quarantine tank. Make sure you set them right side up. If they are upside down they don't seem to be able to right themselves! If they don't open up and go exploring within a half hour or so, your water may be too soft for them to make such an abrupt change. Add a teaspoon of salt per gallon of water and wait awhile longer and see how they react. If necessary, add a bit more salt. Over the next week or two, cut down the salt by doing water changes without any salt added to the new water. They should now be ready to go exploring in your planted tank.
The Olive Nerite is a very efficient herbivore that specializes in algae. Their primary diet consists of diatoms and other small algae, but they will also eat many forms of higher algae as well. I have seen them eat almost all types of algae found in the home aquarium. They do not eat the higher plants. As a test, I have kept them with algae-covered very soft-leaved plants that just about every other aquatic critter eats. They ate the algae off the leaves very well and did not bother the plants at all.
If you are looking for an interesting addition to your planted tank that will also help control the buildup of algae, you can't go wrong with adding a group of Olive Nerites to your tank!