I agree with you that aquaculture seems to have slightly different standards for domestication than Galton’s criteria. Like you said, no fish is really born with an inborn liking to men. I do agree that salmon are low maintenance compared to bass, but really all fish are fairly sensitive and high maintenance animals. For example, compare to any of our domesticated land animals, like chickens or cattle. For the most part, you can house them just about anywhere that is fairly clean and dry, and has food and water. Salmon however, even being pretty well adapted to different water conditions, still require a fresh flow of water, a pretty specific environment that you either have to build in or recreate yourself with pumps. An algae bloom from still water could kill and suffocate all of your fish, whereas huge clouds of CO2 suffocating your pigs and goats are fair less common. Just comparing to the more “basic” livestock, fish have a lot more than can go wrong, that I think makes them much more difficult to raise.