John that's a tough one to answer without a photo. The yellow belly sounds like a bullhead, but one person's idea of "yellow" might be another person's "off white", or "creme colored". Was this fish taken in your BOW, and have you caught similar looking fish in there before? Was the tail heavily forked, or only slightly?

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.