This section of the book is from the "Household Companion: The Model CookBook" book
The variety of edible fish is very considerable, most of them being wholesome and nutritious. Yet white fleshed and red-fleshed fish, oily fish, shell-fish, etc., differ widely in their properties. In general, fish contain less fat than ordinary meat, while often much richer in nitrogenous tissue. The suitability of fish for the table varies with the season, its food supply, the length of time it has been taken out of the water, and the treatment it has received. It is in the highest condition just before the spawning time, being then fatter and of richer flavor. Herring, mackerel, and many other ash are best immediately after being caught, while the ray and some similar fish improve by keeping for several hours.
As a rule, white fish are more digestible than red fish, and the less oily than the very-oily. Among those best suited for weak stomachs are fresh-water fish, such as shad, whiting, etc. Salmon, while the most esteemed of table fishes, has an evil reputation with dyspeptics—this being probably due less to the fish itself than to its condition when cooked and its accompaniments.
Fish of all kinds should be eaten as fresh as possible, and should be kept near the ice until cooked. A fish in good condition should have firm flesh, bright-red gills, and full, clear eyes, with little odor about it. Before cooking it should be thoroughly cleaned and wiped with a cloth wet with salt water. For frying and broiling purposes oily fish, such as shad, mackerel, herring, salmon, and bluefish, are the best, as they do not become dry.