The only difference between the Tiger Nerites and the Zebra Nerites is the shell pattern. It is neat to have a few of each in your aquarium. One of the other reasons people choose Nerite snails is because they won't reproduce in freshwater! These guys are like salmon...they make their way to saltwater to breed. These nerites can grow to the size of a nickel. They are excellent algae eaters and will keep your glass and ornaments and plants clean. They don't burrow. Nerites will be more active when warm, but will survive cold temps. They are very hardy.