you can't put anything in with them except other cuttle's. i think they get pretty big too. around the foot to 15inches. they'll eat pretty much anything just like an octopus, they only live for about 2 years. they have pretty much the same requirements as an octopus. they are very closely related. i've never seen them in a pet store though, only aquariums. when i saw them there they had a bunch of them in together, but they were only 5-8 inches long. they're probably very delicate to have.