I have read that fish oil is not such a great idea health-wise; see this article: http://thehealthyskeptic.org/when-it-comes-to-fish-oil-more-is-not-better. Feed your family cold water fatty fish instead.
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Cod liver oil is the best way to get your Omega 3's, especially the fermented kind. The Weston Price Foundation (and many others) recommend Blue Ice because it doesn't have synthetic vitamins A and D added to it like other brands, and it is suggested to take butter oil at the same time because they act synergistically (you need to make sure you have enough K2 in order for your body to use the Vitamin D). We get the one from Green Pasture Company: http://www.greenpasture.org/retail/?t=products&a=line&i=fermented-cod-liver-oil. It's expensive and it tastes awful, just to warn you (I encapsulate mine for the kids or they won't take it).
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I also personally wouldn't take tuna oil because of the fact that the tuna population has been fished to the point of being endangered.