Most definitely a crown conch. They do eat other snails, but they'll happily eat meaty scraps too. You could try keeping them well fed, and they might be less inclined to eat your turbos. From my experience, they seem like sluggish snails, and I would be surprised if they could subdue a healthy turbo of similar size. To be fair though, my time with them was brief, as they were quickly gobbled up by bigger snails I keep.
Nice picture, by the way! :thumbsup: