I was just talking to my wife about it. Her opinion is that fish in the US is more expensive than chicken and more comparable to beef in that cheap fish is similar in price to cheap beef and expensive fish like expensive beef.

When comparing fish with the meat of terrestrial vertebrates it must always be taken into account that the water content of raw fish meat is much higher, so one pound of raw fish does not have the same nutritional value as one pound of raw chicken meat or beef meat.

If the fish is bought frozen, even more of the paid weight is water, so the water content would have to be accounted when comparing prices.

Fish may be much more expensive than it seems when just looking at the price tag, even 50% more expensive per protein content (raw poultry meat has about 25% protein content, while raw fish fillet has between 15% and 20% protein content).

I wonder if fish is that cheap even in area where fishing is a big industry. Compared to meat, growing and processing fish looks more finicky and expensive, and in particular fresh fish with vitamins and nutriments still intact looks to be pretty big logistics challenge driving prices up.

For instance in Japan fish isn't cheap by any measure compared to chicken or pork for instance.

I just visited Riga, Latvia, and fish seemed to be fairly affordable there.