I wont take over the counter fish oil, the FDA does not test over the counter fish oil capsules. A research study done a few years ago found that most fish oil capsules were high in some toxins such as mercury. If you are going to take fish oil, be sure it is clearly labeled as "carrier free". So far as its benefits are concerned, the Omega-3 aspect is proven fact. The rest of the stories are more or less snake oil theories, without any scientific merit.
There is a prescription form of fish oil available, it is the only one rigorously tested by the FDA and backs its claims with scientific data. Its marketed under the name Lovaza. Mention it to your Physician next time you see him and they'll line you up.