Oh sheesh, someone sold you this? Good grief. Can you PM the store name for interest's sake? Definently not a conch. Conches have two eye stalks (unless they're amputees, like Christy's), and an operculum, the crab-like spade foot. The fighting conch (Strombus alatus) does have the crown spikes, but there are a lot of gastropods that do.
http://www.gastropods.com/9/Shell_1329.html
This is a good example of why we should all strive to use latin names. The average aquarist doesn't realize that there are at least 95 species of conch, not to mention the over 150 genera of gastropods, many of which include animals that could be mistaken for conchs. This is a perfect opening for someone to come along and sell just about anything as a fighting conch. There have been some good discussions of conchs on RC as of late.
Edit - Tiger conch? That's bullshit, pardon my French. A search on Google specifically for "tiger conch" yielded four results, two pertinent (relating to molluscs) and neither from a reputable source. Are we talking about one of the south end LFSs here? Tell them to get you a scientific name. There's no way that's a conch.