they are all from the same family line.
The taste will vary just like any other animal, whether it is natural or farm raised, feed quality and so on.
Rainbows are more of a pink flesh fish such as the salmon. Where brook,brown,speckled and lake trout are more white flesh.
Most if not all restaurant fish is farm raised and taste nothing like a natural feed fish, I think most farm raised taste blan.
FDXX75