Around two servings of fish in a week are highly beneficial for healthy brain functioning. A good source for this oil is found in fish like mackerel, tuna, sardines, oyster, herring and salmon. Thyroid and iodine: The fish head is not preferred by many people but the benefits its holds may change opinions.On its own and as fish head stock it is found to be beneficial in deficiencies of thyroid and iodine. Further it releases gelatin which is so very helpful in maintaining a good digestive system.n fact different parts of the fish like the fish head, fish skin and fish oil have their own set of benefits. ALSO SEE: HEATH BENEFITS OF JUICY WATERMELON. Among all foods fish is considered to be one of the richest sources of protein, especially sea fish.