Their diet is 100% dead animal flesh. If you have too many they will all starve.
What is the problem you are trying to solve? If it's detritus then I'd suggest Cerith. If it's Algae I'd suggest Strombus maculatus and Stomatella varia.
Originally posted by Bang Guy
No more than 5 or 6 Nassarius IMO.
Agreed. I only have about 5-6 of them in my tank. They're very useful and shouldn't be overpopulated.