The CrossFit prescription for fish oil is 3 grams per day of EPA and DHA. These are anti-inflammatory fats needed to counteract pro-inflammatory fats so prevalent in the modern diet. It doesn’t matter what brand you purchase.
As an example, this label on the left is from the Kirkland Signature Fish Oil. All we are concerned with is EPA and DHA. Ignore “Other Omega-3.” As you can see, each soft-gel contains EPA 410 mg and DHA 274 mg for a total of 684 mg. 3 grams equals 3000 mg. Therefore, 3000/684 = 4.4 soft-gels rounded up to 5 each day.
Nutrigold on the right is available on Amazon and contains 1,000 mg in each soft-gel.
Another good option is liquid fish oil. Liquids offer high concentrations and more accurate dosing.