HELP HELP!

[littleboyblue16]

Everyone, today i went to work like always, and this guy came with a bad, it had a chocolate chip starfish! anyways i told him we could not take it in becuase we just don't do that, anyways he just like threw the bag at me, and left me with this starfish! i got a problem though, i have liverock and they eat sponges and everything like that and pretty much their goes my liverock, right now i have him in one of those betta holders in my tank, now i have an extra 10gal on the side, do you think i should just put that up, and put him in their, i really KINDA want to keep him, but i don't since he eats everything, i donno what to do, help me!