This should not be a problem, but you must remember that starfish are carnivores. They do eat other fishes...
Thus said, I had a small size (1.5"-2" tip-to-tip) chocolate chip that i received from a friend. It had been nipped at by his Fiji Puffer.
I had the chocolate in my tank with my trigger and there had not been any problems for several months. ....Until one morning, both the star and the trigger were missing. :scared:
Upon frantically looking around, I saw the star suspiciously perched in the live rock crevace where the Trigger frequently sleeps. I immediately took the live rock out of the tank and tried to get the star off of the rock. But when stressed, stars turn very hard. I could not get it off without hurting it, so i just stopped and put it back in the tank. Me pulling/tugging at it scared it enough to finally 'let go' of the rock/trigger.
I was so sure the trigger was dead.
He didnt come out for hours after that. When he emerged....sure enough, his whole rear right side had been burnt/digested/eaten by the starfish.
I thought he was done for. I put in some slime coat stuff that I had and hoped for the best.
This was probobly around a year ago. The trigger has made an amazing recovery and shows barely any signs of this at all. As for the star, I had put him in another tank with my 'less important' fish. He continued by eating an entire smaller chocolate chip star.
I am now watching him VERY closely, as I have taken down my 'other tank' to create my sump/fuge for my upgrade tank, which will occur soon.
So, let it be known that bad things can happen. But don't let this deter you from buying chocolates. I have always had chocolate chips(5 total) in my tanks and I love them.