Help! Fish in Need.

[martianarts]

I have a yellow tang in my tank, and the other day I bought some distilled water from the supermarket and topped off the tank. We treated the water with conditioner anyway, just in case, and last night the tang looked like it had lost the color in its face and on the edges of its fins. Anyone ever had this problem or know what it might be?

 

[lionstorm]

does he only lose color at night? i know some tangs can lose their color and not yellow fully, which happened with my recently deceased tang (but was not the cause of his death)
You may get more responses from the disease section of the forum, do a search on tang discolorations.

 

[buzz]

This happened at night? Lights out?
If so, take a deep breath. Yellow Tangs, along with many other species of fish, have their color fade at night as a defense mechanism. It makes them harder to be seen, and more difficult to be eaten by predators.
Just to be certain however, what did you condition the water with?

 

[martianarts]

Thanks for the input, I didn't know that it was significant that the lights were out for 24 hours the previous day. This afternoon, we took a look and the tang is doing fine.
We condition the water with AmmoLock. But not a full dose, just enough to cover one gallon.