There's been a lot of talk over the years about how farmed fish contain toxins. The user-friendly Monterey Bay Aquarium's Seafood Watch website offers the truth; although some fish are farmed in ways that render it healthier than others. "Farmed salmon isn't considered a sustainable fish, for example," says Cimarusti. "But for other fish, there are criteria you can use to judge whether or not a farm is doing the right thing by the environment – say, how they care for their fish." Finding the truth can require some digging, including the name of the farm, the fish density in its pens, and whether or not it's treating its fish with antibiotics, among other information.

So should you always buy wild? "Not always," Cimarusti says. "Wild is usually better, though. With wild-harvested fish, you're on much safer ground. Even so, it's sometimes a matter of taste." Tilapia might be farmed and sustainable, but is it a fish you want to eat? "No, it's just nasty," he says. "Tastes like mud."