According to the National Institutes of Health (NIH), 650mg - 900mg of fish oil supplements are good daily intake for good health. A minimum of 2% of the total daily calorie intake should contain omega 3 fatty acids. Consuming too much = 10 times the recommended daily allowance. The trouble is, there is not set RDA for omega-3 b/c it varies by person!

If you're relying only on supplements and not on diet change to include foods that contain Omega-3's naturally, just be sure to be clear about the source of those omega-3's and their total gram count. The FDA has concluded that dietary dosages of up to 3 g per day of omega-3 fatty acids from the sea are "Generally Recognized as Safe." But you can read this article from the AAFP for more details.