Dr Bob,

My Husband and I have a 28"-30" Tancho, he/she might be between 12-15 years old. Back in her day she had won a ribbon or two.

Her / his once almost perfect red circle is today almost completely gone. The circle disappearance gradualy started to change, it seems in the last year, As we opened the pond up this year there was probably half of the pattern left, as of today it's almost completely gone.

I have been told by various people that it could be a water issue, we have never had any issues with the water. Maybe it's the food, we always used a very reputable brand, to that the guy / girl is just getting ....OLD!. We see no other color issues with any of the other koi in the pond.

Your thoughts please...

Sincerely Karin
Lombard IL
Long time reader, first time E-mailer

Hi Karin,

Two main possibilities. The first (and least likely) is a condition the Japanese call Hikkui. It is a genetic failing causing promising young fish to decolorize. They are working hard to eradicate it, mostly by not breeding fish with bloodlines where it exists. Your fish is too old for this.

As a matter of fact, that's most likely the problem. With the exception of the Asagi --where red develops late and tends to be durable -- in most koi varieties, especially the most "refined" (read inbred) GoSanke (Kohaku, Sanke and Showa) red is often unstable and fades or disappears as the fish ages. It is genetic, and it is nothing you did. The red tancho is gone for good. This seems to happen to tanchos more than any other pattern. Just naturally unstable, I guess.

Bob