Fish can be categorized many ways; for example, Mark Bittman, author of How to Cook Everything, divides fish into 11 categories. For simplicity’s sake, we have identified five. Generally, you can substitute any fish within one category for another, although you’ll notice differences in taste.
1. Dark and oil rich: anchovies, bluefin tuna, grey mullet, herring, mackerel (Atlantic, Boston, or King), Salmon, farmed or King (Chinook), sardines, skipjack tuna
2. White, lean, and firm: Alaska pollock, catfish, grouper, haddock, Pacific cod, Pacific halibut, Pacific rockfish, Pacific sand dab & sole, striped bass (wild and hybrid), swordfish
3. Medium color and oil rich: amberjack, Arctic char, Coho salmon, Hawaiian kampachi, mahimahi, paddlefish, pompano, Sockeye Salmon, wahoo, yellowfin tuna
4. White, lean, and flaky: Atlantic croaker, black sea bass, branzino, flounder, rainbow smelt, red snapper, tilapia, rainbow trout, weakfish (sea trout), whiting
5. White, firm, and oil rich: Atlantic shad, albacore tuna, California white sea bass, Chilean sea bass, cobia, lake trout, lake whitefish, Pacific escolar, Pacific sablefish, white sturgeon
Excerpt from Cooking Light magazine, article by Aliza Green