Herschel's got good advice. We had a foster with allergies, and he had to eat fish. Urgh, he smelled terrible from it. We finally switched him to duck and potato and it helped a lot with the smell, but if your dog doesn't have allergies there's no reason to restrict protein sources.
Fish oil is supposed to be good for any dog breed's coat. Canidae all life stages is what we feed our borzoi (a long coated breed) and he does really well with it. It has herring, turkey, chicken, and lamb.
There is a supplement my breeder uses for her show dogs, called "Hair of the Dog". It is a balanced omega fats and herb supplement designed specifically to help with coat health and growth. You could look into that. Her dogs have fantastic coats.