Cypraea tigris cowries are omnivorous, so yes it's possible just wouldn't seem probable but i don't doubt traveller7's observations. (thanks trav.)
not all cowries pose a threat to reef aquaria.
my Cypraea moneta, C. annulus and C. caputserpentis cowries don't bother anything. conversely i had a C. mauritiana humpback cowrie for 13 years which didn't bother anything until it decided to taste one of my T. clam's which had been growing in the tank for 4 years. the cowrie is still alive in a fowlr aquarium. recently spoke with dr. mac about the incident, even showed him pictures and he was adamant it was the purple tang. i don't agree because it only munched on one of the two large +8" clams (next to one another). the nocturnal cowrie was on a rock next to the clam during the day and the clam slowly recovered after i removed the cowrie. to me it would seem unlikely for the tang to do so much damage to one clam and stop there never to munch on it or another one to date after more than a year. i've since added a 2" T. crocea which the purple tang has no interest in (so far). i know that tangs can pose a threat to T. clams but don't think it was the culprit and have to say i wasn't happy getting rid of a cowrie which i had for 13 years. i also had to get rid of my Cyprea arabica's which had a taste for Pocillopora coral. btw i had a money cowrie live for 8 years till a caribbean vase snail ate it.
