A food rich in protein is?

Fish (Cod, Tuna, Salmon) - 17g (35% DV) in 3 oz (85g)

1 gram protein per 4.2 calories
20g (41% DV) in 100g

Other fish high in protein per fillet(3oz or 85g): Tuna (22g), Salmon (22g), Halibut (22g), Snapper (22g), Perch(21g), Flounder and Sole (21g), Cod (20g), Tilapia (17g).

Cheese (Non-Fat Mozzarella) - 36g (71% DV) in 1 cup, shredded (113g)

1 gram protein per 4.4 calories*
32g (63% DV) in 100g

Other cheese high in protein per ounce(28g): Parmesan (10g), Romano (9g), Low-fat Swiss Cheese (8g), Low-fat Cheddar (6g), Low-fat Cottage Cheese (5g). *Low Fat Mozzarella and Cottage Cheese provide the most protein per calorie, full fat cheeses typically only provide 1g protein per 20 calories and are less optimal sources of protein.

Lean Turkey and Chicken (Turkey Breast) - 25g (50% DV) in 3 oz (85g)

1 gram protein per 4.5 calories
30g (59% DV) in 100g

More Chicken and Turkey: Chicken Leg - Drumsticks (60g) provides 16g protein. Chicken Thigh (37g) provides 9g protein. 3oz serving of Chicken Breast (85grams) provides 14g protein.