I have a different opinion (and know it might just be me...)
Fish boards has wide tails and a more flat rocker outline.
So they start very early - great !
But the wide tail is not good when riding the wave, because you can not press hard in the cutback
(in fact you can not press at all if too wide)
Of course you will not move the back foot around - it has to stay where you can turn fluid and from rail to rail going down the line, so because of the wide board, you will not be able to do this very good are my experiences with some fish boards
Then you say: Just put the rear foot more aft ! Well, it works, true - when really aft you can push to both sides yes - but then the advantage with a fish goes away, because you stand so aft that you dont have any glide left
Even with a very wide stance (which is not comfortable either, and it "locks" your body movement options)
I use a big fish board for really light wind and having fun playing around in both small and big waves (when the wind is too light for my "normal" waveboards) - but have experienced above on the different fish boards I've tried.
What works (for me), is a fish board with a more narrow tail
This way you can get both the "going early and glide" and still push to turn on the rear foot.
So would say, that if the board is too big and wide tail, you might not like it in the surf !
Whereas a big fish with a tapered tail (being slightly narrower towards the tail) might work much better
Just an observation I've made through the years - the tail must not be too wide for me, to work in the surf.
Dont know if others has the same experiences (as I've never seen anyone writing about it...) ?
Kindly, Peter Frank