Calico Jack, my calico Ryunkin, has now lost all of his black pigment. The same happened with two orange and black fancies. I've read reports that lighting, ph and diet can all be causing the problem. I've also heard that it might be simply aging. It's odd, because it takes about 6 months for a new fish to lose the black.

My 20 gallon is defintely overstocked (8 goldies,3 cordys, 1 pleco), but I have a Penguin Emperor 400, an internal filter that does about 90 gal per hour, and undergravel filter with a powerhead, and separate aeration. Ph from tap is 4.0, ph in tank runs about 6.5 to 7.0, ammonia is 0, nitrites always run to 0.8 before a gravel washing. 1 year old system.

I use ammonia detox, neutral regulator, Cycle supplement, baking soda, aquarium salt. (Not all at once.) Water changes every two weeks using purified tapwater, with added electrolytes.

I feed Progold, Medi-gold if anyone is acting ill (I have Mycobacterium, confirmed by biopsy in January) in the tank), Jump-Start after Medi-gold, spirulina flakes, assorted treats.

Currently the tank is being treated with Kanamycin and Medigold due to my second outbreak of Mycobacterium. Lost 3 of my babies (Dolly, Tiny Tim, and Groucho) in the past two days.

Anyway, my black moors are nice and black and the fish in question, Jack, is and has always acted healthy. I don't believe the color change is illness related.

Any ideas?

I had goldfish babies and wanted so badly to keep them all, I tried, I really did. Then they started dying. I have had so many diseases and deaths, and I have my self to blame. Finally, I have gotten rid of a couple, a few have died and I am trying to save the rest. Don't make the same mistake I did. Don't over stock. If you kill your fish because you can't afford a mega-huge tank, then they are better off in a pet store. I have not had fish lose color, but I can assure you, that many fish in a small tank, you will have problems, no matter how good the filter.