Yeah, I fifth that on being careful with that thing. It sounds like you know this already, but these guys aren't kidding when they talk about it being deadly. It injects a nasty neurotoxin that kills most people before they can get to the hospital.
Gorgeous animals, though! I didn't realize people actually kept them. Where did you pick up that beauty by the way?
Death is not something people need to be worrying about, if you choose the right cone snail. THERE ARE 500 and more conus in the genus, only a small number, in contrast to the whole, are fish or mollusk specialists. Which may have channel proteins analogous to humans, and venom targeting those MAY cause fatalities. IN the case of conus geographus, 30 recorded fatalities exist.
All others eats marine worms/polychaetes of one form or another! And their venom will more than likely not to much harm to humans.
Just like people who keeps lionfish or fire urchins, as long as you are responsible, and RESPECT the animal's space, and provide PROPER care for them, they make fasinating and wonderful pets.
I can vouch on that, as I have 9 conus ebraeus and 2 conus sponsalis.