Take the one with high EFA and DHA. Fish supplement quite expensive locally. I usually got mine at http://www.vitacost.com

Check the products that said molecularly distilled. Molecularly distilled usually have the mercury/toxins sorted out.

if you are considering to consume omega-3 oil from a natural source, you can up for sardines and mackerel.

They have the highest level of omega-3 that I know off. and they got a load of vitamins and minerals .

Plus they are cheap too.

sardines and mackerel are some of the fishes that are not currently being farmed like other type of fish. They are wild caught.