Coral in freshwater tank

Question
Is it harmful to cichlids to have a piece of blue coral
as decoration.  It's a 50 gal. tank with 10 small cichlids, overhang filter, 25% weekly water change.  Tank is 3 months old, coral is new to tank (2 days). Thank you.

Answer
Yes it is, some corals release harmful toxins when they die (which will be in minutes, in fact chances are it is already dead, but hasn't completely deteriorated), but all corals will reduce the water quality and force you to do daily water changes as long as it is in there.