If you have ammonia in your tank, you shouldn't have anything in there except for maybe live rock. You may want to add some prime to bring the ammonia down or buy some bacteria. If you go with prime, it's a quick fix and you'll need to find a temporary home for your live stock. If you go with bacteria, you should be able to keep your live stock but you'll have to keep an eye on the ammonia and do water changes if you detect any. There are several brands of bacteria. I've had good luck with bio spira but I've also heard good things about Fritz. Polly's pets sell both and I'm sure other Local fish stores do as well. The ammonia might be from the dying candy cane so it might be good to cut the dead head off.