Concerned about my tang


Broke Reefer!
I've noticed my mimic tang flicking across rocks and the substrate the last few days. First time I've seen any of my fish try to scratch themselves on the rocks (though I occasionally see my blenny use her tail to scratch her body). I've looked very closely at my tang and do not see any sort of white spots on her fins or body that would suggest an ich outbreak - in fact I've never seen white spots on any of my fish even though I am sure there is ich in my tank. My tang also has not really filled out much weight-wise - she was pretty skinny when she arrived and I can always see her very full tummy after she eats, but it doesn't look like she's really put any meat on her bones. Now with this flicking behavior, and the crash of my tiny tank, I'm starting to get concerned about her. Is there anything that could be going on other than ich since I don't see any white spots? I've been feeding every other day and nori sheets about 3x per week - should I up feeding at all? There is little aggression in my tank and water quality is adequate, though I recently changed foods and have noticed a diatom outbreak so might have some phosphates in my system from the new food (its a food my LFS makes that has similar ingredients to Rods and they gave me a free bag to try - I'm not really sure I like it though because I think the pieces are too small for most of my fish to really feast on once its thawed). Anyhow, any ideas as to what to do at this point? (And no need to link me to the stickies about ich and treatment - I know them!)
+1 point treating for ich unless you treat everyone and leave your tank fallow for a few months. Plus you don't know that it's ich. As long as he's eating, hopefully that will be enough to help him fight off whatever is ailing him.
Yeah, even if it was ich I have no intention of treating it. It would be impossible to get my fish out of the tank and into quarantine and I'm sure I'd lose some in the process, which I'm simply not willing to do. I'd rather let them fight it on their own and I keep my tank as healthy and stress-free as possible to let them optimally do just that. Besides, there is no visible sign that this is in fact ich.
My Caribbean Blue Tang has been doing this recently too. Same thing, no spots, or anything. Just flashing on the sandbed every now and then. But she's eating like a pig, so I'm not too worried about her. I hope it's nothing and she's just playing around!
Maybe you can try investing in a cleaner shrimp.Your tang should engage it's services in order to rid itself of the irritation.
Samhain, interesting that yours is doing the exact same thing as mine - so weird!

And we both already have cleaner shrimp - my tang could care less about them
Mine visits her shrimp several times a day for a "spit and polish". I've always chocked it up to her just playing around....
I've had ich show up on both of my tangs a couple times. When it happens I make sure every feeding is soaked in garlic (helps their immune system). Other then that, try to keep the tank stress free for a while when/if ick flares up.

I haven't seen ick on my fish for quite some time, but I know it's in my tank. I don't worry about it, but I haven't had any bad cases of it so far *knock on wood*.

I wish my fish would allow the Blood Shrimp to clean them. The shrimp try, but the fish don't know how to take it.I always liked watching that in the tank I had when I was a young lad.