I've had some response to yesterday's post and thought I should include some information on choosing the right oil. There is concern of fish being contaminated with mercury, PCBs, lead, etc., so be sure the oil you buy has been distilled. I bought a bottle of Spectrum Fish Oil from the health food store in Keauhou. Probably because of the prominent "NO mercury,lead,PCB" wording, in red, on the label.
For more information and a comparative chart, you might find this page from David Servan-Schrieber's web site helpful: https://www.instincttoheal.org/article.php3?id_article=55. As he notes, many of the formulas have been prepared for cardiovascular concerns. The requirements differ for uses linked to anxiety, stress or depression. Hope this helps.