When were the fish stocked and where is the pond? This looks like it may be a stunted fish of some age (older than body size would indicate) but poor body condition. Head size is to big for the body. There does appear to be some lighter brown/yellow tint to the fins. It could be a HBG as CB1 notes (a few HBG or even GSF in a batch of BG happens more than us ponders would like). I agree color at this size and condition does not preclude HBG or other mix with BG. If this pond has been stocked for several years with only FH and BG then stunting may be part of the answer.