Horned nerites are a variety of different species all given similar names, but all different colours and shapes.
If you dont have a picture, then a description of size, colour and horn size and number of horns would help.
Just as a basic guide with nerites, they feed on algae EXCLUSIVALLY and will not eat any other foods. They need a tank with algae growth and need to be in small densities in a tank. An average tank of about 25galls cannot support more than 3 nerites. Usually, norned nerites are smaller than thoes without horns, so you could get a maximum of 4 nerites in the 25gal tank.
EDIT: they also need hard water with a pH of above 7 otherwise their shells corrode. Also have a look in the species index of the forum to find a guide to keeping them.
Hope this helps.