But that's still in pitch, rather than acceleration. You would need to go from 0 to 72mph in 1 second to get 3.2g in acceleration
I would be shocked to discover that any fish could reach 72mph in one second in a straight line. Using the language of physics then a change of direction is an acceleration and I suspect that the measurement of the fish by scientists will be stated using the language of physics, not how we pilots restrict the use of the word to flight.
major.tom refers only to the 'G' force not the speed.