I think fish oil is good but you have to be careful what you take. I have read that you need to stay away from certain fish oils like anchovie oil which is included most fish oil pills. The best form of oil is Flax for omega 3's along with salmon and cod oil and of course if you are not allergic to shellfish then also krill oil. There are some things in flax that are not in cod oil as with the reverse for each. That's as much as I know. Personally I cant take krill because of my allergy to shell fish so I take organic flaxseed oil and a cod liver oil alternating between the 2. Of course if you eat enough fish then you wouldn't have to take a supplement but who eats that much fish etc...
Steve