Hi Jess... This subject comes up now and then..

The way the oils are processed, removed from the fish bodies
removes heavy metals etc. I believe that there are about 20 steps involved, so this complex task does not have many places that do it. A while back consumerlab.com tested over 15 oils and all passed.

Today, the question becomes which type of oil should I use?
We have today, concentrated oils (double strength).
We have oils enteric coated for reducing fishy burps.
We have oils that have much more EPA to DHA ratio.
We have oils that have more DHA to EPA ratio.
We have DHA only oils.
We have EPA/DHA vegetarian.
We have an RX Fish oil called Lovaza.

Both SAMs Club and Costco sell enteric coated double strength
capsules reasonably priced. This is what we use.

OmegaBrite has higher EPA ratio...which is the anti-inflammatory portion and was originally made for bipolar studies and now for bipolar patients to use. It is only available on the net.

The Vegetarian EPA/DHA has a very LOW amount of EPA in it, so would not be a good choice for you. You want the EPA portion mostly.

NatureMade makes one. Many good companies make them now.
If you stay with a well known company that is better.

You do not want to use Cod Liver oil. It is mostly A and D with a small amount of EPA/DHA. You cannot safely increase dosing with this. Some health food places with poorly trained or untrained sales people push this, so don't fall for their pitches.

Take the oil with food. And divide up the capsules if you take more than one. You can start at one a day until you get used to the GI effects, and increase. For good anti-inflammatory effects you need at least 3 regular strength or two double strength ones daily. The enteric coated type reduce complaints of burping. I have found that the more burping indicates poor stomach status, and with time it corrects itself and goes away, if you get it at all.