Haggai Cardinalfish gone white

I’ve been on holiday and left my tank with two heaters (which kept the temperature to 25degrees) and feeding from one of my family. I have come home to my cardinal fish both on the bottom, moving and one being very white? He’s starting to get his black stripes back from white to slightly closer to black over the last ten minutes but still on the bottom moving wierdly? Ammonia: 0 nitrite:0 ??