The "fishy" taste is likely indicative of a higher omega 3 content, you get the same taste from 100% grass fed and finished beef and buffalo due to the higher omega 3 content.
Grass fed beef tasting "fishy"? I've never experienced that and can't imagine how it would work.
More expensive grass fed doesn't have this problem, so it likely has to do with diet or the cut.
I am not sure this is true. I live in a country (NZ) where most cattle are grass fed their entire lives. This is supposed to mean higher omega 3 content but I have never tasted a fishy taste. Not even once.
If grass fed and fishy taste are corrolated, I suspect there is another cause. Maybe organic fish containing grass fertiliser?
Brown egg layers are apparently more prone to this issue