Definitely a pond mutt of unique genetic origins. But, one with a certain presence. Body is not bad. Has a sense of strength about it. Personally, I think a pond of Gosanke looks all the better when a plain sort of kawarigoi is mixed in... a Chagoi or something. The contrast makes all the koi look better. In a pond of Kohaku, your kawari would be like an uncut opal in a field of rubies and diamonds.
Of course, if it really means no more than 30 bucks to you, then ditch it and make room for the best Kohaku your budget can accomodate.