GBH has been lecturing you (here, another one here, and another here) on the importance of a healthy diet as the foundation for preparedness. Good nutrition builds healthy individuals, who are stronger and make better decisions. From there, the neighborhood, the community and—that's right—the whole dang world are peopled by survivors.

(Hey, I admitted to lecturing! It's a labor of love, people. We have a new world to build.)

Eating fish is a good habit to get you started. But as with everything good for you, there is a little knowledge involved. (Yup, health is like doing math. But once you know it, there's nothing you can't figure out.) There are some kinds of fish to avoid at times , and times when to avoid certain kinds of fish.

Fish protect us, for heaven's sake! Right now, science is using the properties of bluegills to enhance national security . Fish are the planetary equivalent of blood cells—they run things. Everything eats fish or eats something that eats fish; they populate and regulate water, which is the prime element in life; they have a central place in both science  and religion ; they are sushi , which is the royalty of food (no arguments allowed). Without fish, I declare here and now, life itself would be impossible.

Just look both ways , no matter what you had for lunch.