Colour Fading!

[Tropix]

If anyone knows why all the colour has faded from my neons and tiger barbs, but if i leave the light on it comes back, today it was off only for a few hours and they all turned pale.We are putting the light on for the right amount of time as well, any ideas

 

[WILDER]

Need to look at water stats in ammonia,nitrite,nitrate,and ph, some fish when lights are out do go pale, if the colour is returning when you switch light back on, i don't think there is much to worry about.