By the looks of the picture you definately do not have a Tiger Cowry (C.Tigris). What you have is in the family of the Reticulated cowry - a group of several different cowries that look almost identical making I.D. rather difficult (C.Reticulata,C.Arabica,C.Maculifera and so on)
The good news is they are probably less predatory than a true C.Tigris,feeding mainly on algae. You should have no difficulty keeping them in a well established reef aquaria. I've kept similar specimens for several years.
Good luck to you!!