It's the only snail in the tank. I had two other smaller snails a few months ago that didn't last long. There seems to plenty of algae in the tank.
Unfortunately I don't have any chemical testing kits yet so I'm not sure where my phosphate, ammonia, and Nitrate levels are. The only thing I've changed in the tank is added an LED light, and got my sump up and running with the overflow (white PVC in the pic) and a protein skimmer. It seems like the snail started having a hard time after this.
As a general question, do they need different kinds of algae in their diet? Should I be worried about adding any extra food other than the algae growing in the tank?