Eating cold-blooded creatures

Fish are famously cold-blooded creatures. This has a few consequences for carnivoures like me.

The bad news, fish goes bad in the refrigerator faster. According to physicist Peter Barham's The Science of Cooking, p. 92:

Many fish lie in cold seas, so that the enzmes they use to metabolise food need to be active at low temperatures (sometimes as low as 4C). The Enzymes in meat, by contrast, work at body temperature (usually 36 to 38C) and are only very slightly reactive at low temperatures. The end products of some enzymatic reactions will start to accumlate once the fish is dead and its circulatory system is no longer functioning. It is the waste products that give fish its characteristic smell....Remember that the enzymatic reations that can themselves consume the flesh cannot be delayed by refrigeration as they can for meats, so you need to eat the fish before its own enzymes eat it.

The good news: Fish-fat tends not to have less artery-clogging saturated fat, as found in beef. In particular, from page 12:

In fish and plants where the temperature can be much lower [than in mammals], saturated fats would tend to solidify and be difficult to use [by the fish or plant], and may even form constrictions in the circulatory systems leading to disease, ect. So they tend to use the...unsaturated fats for energy storage.