There is Omega 3 in flaxseed, english walnuts, canola oil, chia seed, and spinach. Marlin, tuna, shark, swordfish, and king mackerel are found to have high levels of mercury. These fish could pose a health risk due to heavy metal exposure. Eating contaminated fish is the number one cause of mercury exposure in America. See https://www.nrdc.org for more information.