First I will give you a little background on my setup. My aquarium cycled about 3 weeks ago and I have not experienced a mini cycle since. I have a 58 gallon DT with a 20 gallon sump. Im running an sc-150 cone skimmer and have cheato in my sump. Water parameters are 1.22 sg, 0 ammonia, 0 nitrite, 0 nitrate, PH is 8.2 and water temp is 80 degrees. I have a damsel in the tank that has been happy since I started it. I added a firefish about a week ago and he has been happy and eating well. I did a 10 gal water change last night and made sure that the salt was mixed properly, right temp etc... I have a frogspawn coral in the same DT that is open and extended and happy. The firefish is in hiding now and won't even come out to eat. I am pretty sure he is going to die. I am really discouraged by this because it makes no sense. Is there anything that I am missing here? Thanks.