[Pseudoscience-is-malarkey (OP)]

My doctor informed me of my low vitamin d levels and suggested more fish in my diet, which is not a problem for me as I love to eat them, especially salmon (grilled and served with a kale salad). What is your favorite fish and how do you prefer them cooked?

[Colin2B]

Salmon and trout are good, so are Hake and Pollack.
I like most fish

[alancalverd]

A vote for pollack as having bigger flakes than cod, in most white-fish dishes except fish'n'chips where the tighter texture of cod makes it easier to eat with your fingers in the street.

Herrings in any form, bloaters, kippers, Bismarck, rollmop, dill cream - perfect breakfast or salad lunch.

Eel, jellied, smoked, fried or in a pie, is unbeatable but sadly a bit endangered by illegal trapping of (delicious) elvers. And you have to respect a fish that can swim backwards, travel across a field, change sex, move from fresh to salt water, swim a thousand miles  to mate, exude a slippery gel to increase its terminal forward speed, find its way back home years later to give birth in fresh water, and live for anything up to 100 years. Definitely food for thought!

Mackerel - lifesaver! I went sailing many years ago with a crew that included the current girlfriend who was a nutritionist. She insisted on provisioning the boat and managing the galley. Everyone else got very sick and took to their bunks. I ran a trolling line behind the boat and caught loads of mackerel which the others refused to eat, so I ate nothing else and ended up sailing the boat home singlehanded.

[Pseudoscience-is-malarkey (OP)]

How does bigger flakes amount to better tasting fish?

[evan_au]

I enjoy salmon.

But I am puzzled about how fish have lots of vitamin D, given that they don't get much exposure to UV light.
- I have heard fish promoted as a source of "good" oil - I often hear people talking about "Omega 3" fish oil.
- But I understand that the fish get this oil from the microscopic food they eat.

[alancalverd]

How does bigger flakes amount to better tasting fish?

The taste is much the same as cod, but appearance and texture are part of the pleasure of eating.

[alancalverd]

I am puzzled about how fish have lots of vitamin D, given that they don't get much exposure to UV light.
- I have heard fish promoted as a source of "good" oil - I often hear people talking about "Omega 3" fish oil.
- But I understand that the fish get this oil from the microscopic food they eat.

Cod liver oil also contains vitamin A and vitamin D. Historically, it was given to children because vitamin D had been shown to prevent rickets

Which is a bit odd as cod is a demersal hunter - its prey lives well below any UV radiation, and arctic squid aren't exactly microscopic.
CLO was a standard daily ration in primary schools in my youth, along with milk and occasional orange juice.

[Pseudoscience-is-malarkey (OP)]

While mingling outside is not encouraged we might have to up our fish consumption or take those small, golden, caviar looking vitamin d supplements.

[Petrochemicals]

Scallops, lobster, crab, scampi, razor clams, oysters.

[alancalverd]

Oysters, eh? Nothing quite beats COVID, but norovirus comes a close second for a taste of  the afterlife. A bit like training on the hairy, scary Harvard before the Spitfire. 

[Bored chemist]

But I am puzzled about how fish have lots of vitamin D, given that they don't get much exposure to UV light.

In humans the synthesis of vitamin D uses UV light, but it's likely that other animals are able to synthesise it via some other pathway.
Most animals can synthesise their own vitamin C, but we (essentially the primates, I think) lost that pathway.

I'm very partial to trout with almonds, but to be honest most of what I eat (and greatly enjoy) is deep fried, battered "whatever"- it's labeled as cod, but  I'd not trust it without a DNA test.

[Colin2B]

But I am puzzled about how fish have lots of vitamin D, given that they don't get much exposure to UV light.

The plankton do synthesise it, then it gets past up the food chain.

[Petrochemicals]

How does bigger flakes amount to better tasting fish?

The taste is much the same as cod, but appearance and texture are part of the pleasure of eating.

the cod we eat can be quite small so they dry, plus less fresh fish (kept because of the price) is less oily moist etc. Go to a really big fish shop, somewhere that has a fleet and see if they have a chip shop. But i guess like tuna the bigger the more expensice the cut.

Oysters, eh? Nothing quite beats COVID, but norovirus comes a close second for a taste of  the afterlife. A bit like training on the hairy, scary Harvard before the Spitfire. 

Yup, they farm oysters somewhere near the thames estuary mouth, they have to take the oysters and purify them for something like 3 months. Exotic, like Typhoid fever.