ORIGINAL: bowman15
The rest of the meat looked pretty good, but this was the first one he cleaned and the first fillets from one I've seen since Duane's demo at Bass Pro last year, so I wasn't too sure. Maybe we'll try the next one.
The red meat that runs down the lateral line of the fish is not worth eating. Yuck. Sometimes male bighead carp, and usually male silver carp, can have a redder-looking "white" meat that is OK to eat. This gets worse when they are spawning. I think I can tell the difference between males and females by flavor, but maybe I am fooling myself and it is only the color (males a bit darker, even when cooked). Whatever, the difference in flavor is not extreme, between males and females.
For the fish that are losing weight, there is a lot less meat in general - lots of bones and not much meat, and what meat there is, is not very appetizing. If you get a bighead carp that looks like a tadpole, all head and no body, it is probably not very good to eat. If you can see the edges of the skull, and the meat looks concave behind the skull, it is WAY too far gone. The flesh gets nasty long before that happens.