Fauna is 25 lbs and gets 2 pumps of pollock fish oil a day. She's very active, so I give her a little more than the recommended dose of 1 1/2 pumps. Her skin and fur are BEAUTIFUL! I've been telling all my friends with long-haired dogs to add it to their dogs diet.
This is what I give her: http://www.grizzlypetproducts.com/pollock_oil/index.html Wild caught from a sustainable fishery!
I give mine sardines. I have 4 dogs, and there are usually 3 or 4 sardines in a tin, so the corgis get a whole one, and the min pins get a half. They love them in their dinner! I just make sure to get the sardines in water, or oil. Their coats are beautiful! Ein is a shorthair corgi and we always get comments on how soft he is. Lilly is a Fluffy, and her coat is gorgeous anyhow, but the fish oil does make her coat even softer.
I started giving Max fish oil over the winter because he gets such dry skin and chews the inside of his hind legs raw. It really put a stop to it. It also helps control normal shedding...of course corgis don't shed in a nomral fashion but I do see that it makes a difference. After I saw how well it was helping Max I started giving them to Katie too. They both get one capsule with their food at dinner. Their coats as soft and shiny.
Depending on your food some food have fish oil in them. If your pups that young I would do 1/2 a tsp. a day. Just mix it in with her meal. And as your pup gets older you can add a whole tsp. a day. And I just get the fish oil for humans from Costco.