The nerites (Neritidae), also known as racing snails, are very popular. Their beautiful coloration is one of the reasons for this, but also their excellent properties as algae cleaners, which (if you keep enough specimens) reliably keep the aquarium glass clean. Plants, on the other hand, are left completely alone. And there is no unwanted mass reproduction, as the larvae of these snails can only develop in the sea. The only downside of nerites are the white, chalky egg capsules that they attach to solid objects everywhere.
Nerite snails are among the exotic animal species that became known in Europe very early on, as their pretty shells have always been used as jewelry. The animals, which are very common in nature, are also traditional food for the local population. Vittina turrita was originally described in 1791 under the name Nerita turrita, later transferred to the genus Neritina, where it was listed in the subgenus Vittina until recently. In a major review of the nerites – a taxonomically difficult group – Vittina was elevated to genus rank (Eichhorst, 2016), so since then the species has been called Vittina turrita. The genera cannot be distinguished with the naked eye; this can only be done with microscopic techniques.
At the species level, non-specialists are completely overwhelmed by Neritina in the broader sense. Although a “bible” for all nerite snails was published in 2016 (Eichhorst, T. E.: Neritidae of the World, Vol. 2. , ConchBooks, 672 pp., num. color figs, 170 pls, hardcover), this proud work also has a proud price. Aquarists are usually guided by the shape and color of the shell, the coloration of the underside and the operculum and its shape, which is sadly not visible on the living animal.
These characteristics are completely identical in the zebra snails and the onion or tractor snails. Nevertheless, the latter, which derives one of its popular names from the fact that its shell pattern is reminiscent of the tire imprints of a tractor, is currently considered a valid species named Vittina semiconica, after V. semiconica was previously considered a synonym of V. turrita for many years. We obtain both forms from the same supplier in Indonesia.
Many unanswered questions can probably only be resolved when more aquarists become involved in breeding these snails. This requires a saltwater aquarium, but that should not be a fundamental obstacle. Vittina have separate sexes, so there are males and females, although they cannot be distinguished externally. However, it would be proof of species identity if eggs from a breeding group with phenotypic zebra snails spontaneously grew into tractor snails. The adult snails live exclusively in fresh and brackish water.
For our customers: Zebra snails have code 485483, the onion or tractor snails have code 485502 on our stock list. Please note that we exclusively supply the wholesale trade.
Text & photos: Frank Schäfer