Ok. I've never heard them to be aggressive with each other. Here's a quote from LiveAquaria.com:
The beneficial Fighting Conch is not as aggressive as its name implies. Though a male Fighting Conch can be territorial towards other males of its own kind, the Fighting Conch is peaceful towards other tankmates. The Fighting Conch is a suitable addition to any home reef aquarium, where it will use its excellent sand sifting abilities to clean and aerate the substrate. Praised for their hardiness, the Fighting Conch requires open, deep sand beds in which it can forage for food. Though multiple Fighting Conches should be housed in larger systems, single specimens are suited for any size reef aquarium. Keep in mind that the Fighting Conch has a voracious appetite; as such, supplemental feeding is required in smaller systems and recommended in even the largest aquarium setups.
Classified as an omnivore, the Fighting Conch will consume detritus from your aquarium substrate. Supply pieces of fresh fish and dried seaweed, as well as high quality frozen foods to supplement the diet of the Fighting Conch. Like other invertebrates, the Fighting Conch is sensitive to high levels of nitrate and will not tolerate copper-based medications.
Ask Aquahut for a latin name (any responsible LFS should have access to it) and research that before attempting to introduce them to your tank. Fighting conches are the "industry standard" when it comes to sandbed conches and I'd view all others as "we got the wrong conches in stock so sell these as better than fighting conches until they're gone"