Its a strombus snail and will reproduce in your tank. They can subsist on whatever grows in the tank very well. If you have several you will start seeing babies and egg packets on your glass. They need flat spots to lay them on. Keep your eyes out. I took mine from the LFS and have LOTS of babies now . Nice little snail. BTW they won't get but half an inch big max so don't worry about them getting giant.
I looked again and it could possibly be a tulip snail but i really really doubt it. If he starts to get bigger than half an inch then youll know. Tulip snails are predators and need to be removed from the tank. Like i said i REALLY doubt it is one...
nassarius sail is my vote. I have many of them, they are good for keeping sand beds clean and digging in the sand and moving water and O2 into the sand.