Because of continuous touch with nature, wild species are better in taste

Depends on the pollution status of the natural conditions. Nowadays a farmed catfish tastes better than that acquired from polluted canals. But it is true some fishes undergo physiological changes effectively like fat accumulation in response to natural environmental cues only. That largely influences the taste.

Intensively farmed vertebrate species in often cramped conditions usually don't move as much as their wild brethren and thus their flesh does not have the same consistency and texture. You can see the difference even as a layperson looking at farmed salmon with the characteristic fatty deposits between the myomeres and the muscle not bouncing back, when you apply a little pressure - compare that with wild salmon of usually darker more intense orangy/pink colour and firm muscle. The colour is due to the crustaceans in their wild food, while farmed salmon is raised on feeds based largely on soya (not enough cheap fishmeal available) and gets supplements giving it a light pink colour shortly before slaughter. That's not to say to automatically all species fattened in culture are bad - some less intensive processes don't need as much artificial feeds, antibiotics and other supplements. Especially in forms of polyculture that have existed in Chinese traditional freshwater culture for millennia they may also use part of the natural productivity thanks to a wider range of species raised together using all ecological niches in a waterbody. Such more extensive or semi-intensive forms of aquaculture mimic natural conditions to produce the different textures and flavours of natural habitats, but are currently not competitive with intensive farms not paying for the environmental cost and other ramifications they externalise on the environment and society.

I agree with Cornelia E. Nauen In Washington State, United States, there are farmed and hatchery salmon. The farmed salmon are raised in pens their entire life and because of their feed and lack of exercise, they are not considered as tasty as wild salmon. However, hatchery salmon live a portion of their lives in the wild and in my experience, species that live for years in the wild after initial rearing in a hatchery are equivalent in taste to wild salmon. Examples of such species are coho and Chinook salmon, Oncorhynchus kisutch and O. tshawytscha.

It varies tremendously depending on the diet and exercise status. Plus, there are personal preferences that come into play. Doc Donaldson, a prof I had at the UW, conducted a taste test with some of the trout he was raising. The only difference in diet/exercise was colorings fed to color the flesh. North Americans said the red-fleshed fish tasted better, Northern Europeans said the pale-fleshed fish were tastier. In this case, taste was in the eye, and mind, of the consumer.

I think that wild stocks which grew in less polluted and rich waters will taste better. This I think is because diet preferences, age and the freedom of movement are in favour of the wild.

If pollution and poorer water quality are the reasons for farmed fish taste inferior, when the two characteristics are corrected in fish farms then the farmed fish should taste as good as the wild. In agriculture and animal husbandry the domesticated do better and tastes better. One breeds plants and animals even to create desired tastes an flavours! Perhaps this is only a matter of duration of domestication, which in comparison with agricultural plants and animals is far too brief for fish - it might be only a matter of time for farmed fish to catch up!

In Pacific Salmon there are significant differences in flesh "quality" depending on the species, specific stock, and maturity. Some have very red flesh, some of the same species very pale due to different foods. Some accumulate fats as they mature in freshwater after months of not eating while others mature in the ocean and have a very non-fat flesh. All sorts of different tastes and flavors. Each has its proponents. So, in my mind, one is not "better" or "worse"; it is just what I prefer. As noted above, if you get off flavors like a muddy taste (which trout acquire in warm water here) then changes in culture or maybe just harvest time can modify this. Aquaculture products are "designed" for a market and what one person prefers might not be what another does. Develop markets and meet their expectations.