As a seafood lover, I try to stay abreast of which species are deadly killers. An Eco Defense website has a nice chart telling you which ones are safe to eat (including catfish, clams, crabs, scallops, wild salmon) and which are slowly poisoning you (orange roughy, shark, swordfish, farmed salmon). There are several others on the list, and it also gives info on which are being over-fished, and how much of the deadly ones you can eat, based on gender and age (yours, not the fish’s). Pay attention to locations on the chart and at the supermarket; for example, most Alaskan fish is ok, but if caught from different areas or farmed, it may contain unsafe levels of mercury or other toxins.