Eating fish can be a smart choice. It's a lean protein with great health benefits. But sometimes fish can be bad for you, and sometimes it's bad for the environment.

Seafood can be contaminated with high amounts of mercury or PCBs, causing ill health effects. And some varieties of seafood have been overfished or caught in ways that may cause lasting damage to our oceans and marine life. When you're at the store or ordering in a restaurant, how do you know which seafood to choose?

When in doubt, there are seven basic rules that you can follow to make smart seafood shopping choices. Check out our quick tips to find out what you can ask yourself in the store or at the table. We also have specific advice about America's favorite types of seafood and a handy guide to what's OK to eat and what you should avoid.

Use this advice to choose seafood that's good for your health and the health of our oceans.