usually fishes will turn dark when become stressed or they might want to blend to their dark surroundings.Amok said:
the experience i've got with my pb is that they turned dark when i switch off the lights. but will change to their normal color when the lights are turned back on. have you tried leaving the lights on for a longer period of time as most of us will turn off the lights after feeding.
i can't think of anything that would help on the part on your pb not being able to stabalize itself. but i think it might be caused by internal infection. try not feeding it for a day or 2 to see if there is signs of bloating.
