My first thread, i should've joined a long time ago. New to the hobby and started off pretty good. I currently have a fowlr 55 gal wet/dry setup. Had some nice fish like huma trigger, niger trigger. Clown trigger, maroon clown, porcupine puffer, yellow tang. Well all perished except the yellow tang due to ich. Now tang has this pinkish blotch and is flashing on decos and rocks. No signs of ich. Stopped eating pellets but still eats his algae. Looks healthy otherwise. What could this be?