fish doing headstands?

[rdelbalso]

I think my fish have ich and I started a coppersafe treatment Wednesday. Since then and maybe before the treatment, I have noticed my tiger barbs doing headstands. I was just watching them and now they are actually going inverted for short times. What can I do? pH=7.4, water temp = 82, amonia=0, nitrite=0, nitrate=0. 20gal tank with 3 tiger barbs, 1 pictus cat and 1 rainbow shark.
the shark and pictus cat seemed to have reduced their flashing and their fins are no longer folded.
thanks

[fishaddict]

Ive seen this happen when my barbs are stationary. They always seem to go nose down. Ive read its an indicator of nitrites but apparently you dont have any and neither did i. I think its ok, its just something they do.

[wetmanNY]

I've been associating the headstands with nitrates >40ppm, rather than nitrites. A water change seems to reduce the headstands.

[RENEGADE]

IMHO i think they "kick the buckit" at that point