As fish has such a small amount of connective tissue, it requires very little cooking. If it is overcooked, the flakes fall apart and the fibers become tough, dry and tasteless. There are several ways of cooking fish, but the cooking process should, in general, be short and gentle. Although fillets are more popular, most cooks agree that fish on the bone – as with meat – has more flavor.

Source: ezinearticles.com