Thank you. I'll do a melfix dip. No changes in parameters. I've been adding iron supplement last few days. Possibly a coral sting - frogspawn near by. Nothing else that I can think of would sting it. Would frogspawn do this?UH OH! looks like you will be needing some ati bacterial dip like iodine or my favorite Marne melafix. Just follow the directions and you should see some improvements,the sooner the better. Also good flow and new carbon will help remove and deal with any mucus sloughed off from the irritant. Also has there been any changes in parameters? A possible burn from salt creep or other coral sting?damage to the tissue from an abrasion? All sorts of things can lead to an opening to infection.
Just to update you. Did the dip, and did place my Coral Beauty, because I'm also not sure he didn't nip him, and he nipped my fungia plate. He is doing just fine, and looks back to normal. Thanks!At night there can be long sweeper tentacles that come from the frog spawn and hammer corals so this is certainly possible. The sarco should bounce back though.