trochus: naturally feeds on algae, cyanobacteria, and diatoms
astrea: cyanobacteria and diatoms..and algae on sides of aquarium
Cerith: detritus, uneaten food, decaying organics, fish waste, and several types of nuisance algae.
Nerites: algae, cyanobacteria, and diatoms,film algae eater, grazing on other surfaces, such as the sides of the aquarium
nassarius: detritus, uneaten food, decaying organics, and fish waste.