The Marine Conservation Society's Guides to Sustainable Seafood provide comprehensive listings of the best sustainable choices, the fish to avoid completely, and the fish that can be eaten occasionally to limit pressure on their stocks.
The App allows you to search by common fish name and provides all the information from the Good Fish Guide, both at a glance, and in full detail if needed. There's also a downloadable pocket version for those who prefer it.
Sustain: Sustain The alliance for better food and farming advocates food and agriculture policies and practices that enhance the health and welfare of people and animals, improve the working and living environment, enrich society and culture and promote equity.