Get your omega-3 fatty acids from either fish or flaxseed (or other seeds).From Science Daily:
Nothing fishy about health benefits of plant-based omega-3 fatty acid
Increasing the amount of omega-3s in your diet, whether from fish or flax, will likely decrease your risk of getting heart disease, according to Penn State nutritionists. A substantial amount of evidence exists supporting the heart-health benefits of eicosapentaenoic acid and docosahexaenoic acid (EPA and DHA), marine-derived omega-3 fatty acids. However, much less evidence exists to demonstrate the positive effects of alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid.
EPA and DHA can be found in seafood and fish oil, and are often consumed in the form of dietary supplements. ALA is found in flaxseed and its oil, vegetable oils, and some nuts, and is now available in supplement form. EPA and DHA have been available for much longer. Other sources of ALA, EPA and DHA are fortified foods such as orange juice, eggs, peanut butter, margarine and bread, among others. While there are many other omega-3 fortified foods in the market place, most are relatively low in omega-3 fatty acids.
Omega-3 fatty acids are considered essential for human health, but the body does not produce them -- therefore they must be consumed in order to maintain appropriate levels.
In reviewing existing literature on the subject, the researchers have come to the conclusion that ALA is likely just as effective in preventing cardiovascular disease as EPA and DHA have proven to be, as they report on the current issue of Advances in Nutrition.