My Fish lost all its color!

#1
After having this fish for over a year I have FINALLY figured out what it is. For how common this fish is it was surprisingly difficult to figure it out. Google kept telling me it was a clown loach. It's a Pangio (Acanthophthalmus) kuhlii or Kuhli Loach according to aquahobby. Here is my problem with him though. He turned WHITE! He has been in the same tank with the same mates for years now. The fish have never bothered him before and have successfully mated and raised offspring without considering him a threat (poor eggs). All the other fish in the tank look like they went through the techicolor process. The Jewels are bright red, the zebra's dark orange, the Acei darkened up and even the Yellow labs have started to show off their black on their fins again. So what have I done to him that he lost his color?

The only thing I can find is that the water has been too cold for him as the heater broke over Christmas, so he went three days at about (72-76) degrees which is only slightly colder than optimal (75-86).
 

#4
I never thought about it, But I just went back and checked thats 1 over what it should be (should be 7.0 Ph). He has been fine so far though in the same Ph level, I know that might not mean much but after a few years the same way I would find it hard to believe he would suddenly stop liking the water. (unless of course the water changed, which it didn't)
ammonia, nitrates, nitrites all good...... I did get a new food for the cichlids as Petsmart stopped carrying the brand I was using. Currently using Hikari Gold. was using Omega One. (funny though they still sell this brand in flake)