Nerite stocking density
Nerites are a fantastic addition to a tank, especially planted tanks, but one must take caution when choosing how many to add. While nerites are small and won’t produce viable young, they are very specialized feeders. They graze on biofilm and flat algaes very efficiently. It can be a big challenge to supplement their diet. Occasionally they will take something like a vegetable pellet, blanched vegetables, or gel foods (Repashy Soilent Green), but its usually only if they are quite hungry already.
Because of the challenges on feeding them, I recommend only stocking a single nerite per five gallons of tank space in a mature tank (running over six months) or one nerite per ten gallons for newer setups. Its important to consider this especially when dealing with an algae outbreak. Adding a lot of nerites will certainly get rid of the algae quicker, but the tank won’t be able to sustain them once they have cleared the glass and decor of edible goodies. Often you will see nerites who are overstock in a tank survive for a few months before they start dying off one by one. In a tank that can support their needs, they will often live two years or more.
Please also consider their needs pertaining to water chemistry. Hard or at least moderately hard water is required for them to thrive. Otherwise, etching and degradation of their shell will occur. Check out an assortment of nerites and other snails in my freshwater snail species gallery.