A lot of nerite species can move freely around FW and SW such as Vitta usnea. The downside is they don't breed readily in FW unless you are lucky enough to find the European species which do breed in FW. A lot of species from Philippines and Indonesia require varying salinity in order to breed. The bigger challenge is raising the larva to snail stage. The larva called vellifers thrive on phytoplanktons and microalgae. Failing this, they won't be able to survive to the snail stage.dthomasi;2677082; said:Freshwater? I'm trying to remember why I didn't get any when I looked into them long ago.