He is missing quite a few vitamins and minerals with this diet, maybe your vet can advise with suitable all round vitamins for a young dog but for a start you may wish to add some biscuits to his diet to at least give him some calcium for his growing bones as there is no calcium in that diet (unless the fish has bones in it).
I would advise that you either change his diet or read up more thoroughly on home cooked foods for dogs. (Not intended as a lecture just advice.)
I fed a raw diet so if I gave those things to my dog I would also include the following too bones, kelp, egg, egg shell, cereals, bran, offal, wheatgerm, omega 3,6,9 oil, herbs but not necessarily all in the one meal and I never mix cereals with meat meals.
