Fish is OK but not too much tuna or fish that may have trace amounts of mercury and of course watch for bones. I think my kid was about 16 months when I started giving him fish sticks and he had a little salmon before that. He's been eating tuna casserole about twice a month since he was 18 months old. How much milk depends on how much other dairy they eat. A serving of milk is 4 oz at that age and you want at least 3 servings a day. Other sources of calcium include broccoli, spinach, okra and calcium fortified juice, pasta, cereal, bread or soy products.