I have a juvenile yellow tang that I just recently added to my tank. I don't have a qt, because I don't have a job and I'm still pretty new to the hobby. I've had ich before, so I know what it looks like, and this looks exactly like ich, but he's had it for about a week and a half and it shows up at night, but its not there in the morning. It also hasn't showed up on any of my other fish in the past couple weeks. He swims around, he's very playful still, he is a very healthy eater (diet consists of brine shrimp and garlic soaked green algae strips with the occasional hair algae in the tank). Is this possibly a stress-caused disease? I'll post pics as soon as I figure out, but it really looks like nothing more than ich with a little loss of color.