Though I like fish for health reason, I seldom eat tuna or some other large fish since about 2-3 years ago for environmental concern. But which fish are caught in a sustainable manner and are low in mercury and other harmful contaminants?
Here comes Monterey Bay Aquarium's Seafood Watch Program:
This program provides easy to follow, visually intuitive lists of fish in four different categories (green being the safest and the most environmentally friendly to eat). It also provides free iPhone and Android apps, so you can check which fish you should order at the restaurant, or which one to buy at the grocery store.