once yellow turns brown, its pretty much dead. yellow leathers r bad shipper. i had 2 shipped to me in the past, and both arrived all brown up. dead after 3-4 days.
well, i e-mailed the place i got it from about the condition it arrived in. i said i'd wait till tomorrow and let them know what happens. is it going to do anything to my other coral, leaving it in there dying?
it will normally disintegrate in a few days. if u r positive its dead, then take it out. it wont kill ur other corals, except dirtying the water. do a water change if anything.