Devil Fruit effects on different Species

If Oda decides that something like that exists, than he has to counter-balance it, like he did with the "normal" devilfruits.

So the fish who ate it, can't go outside of the water or he'll be unable to move.

Which would be rather pointless.
Because the story is about the strawhats.
Ruffy can't fight someone who can't get of out the water and he himself can't fight in the water.

But who knwos. Oda could make it happen if he wants (hope he doesn't though)

:-D

hmm... here's a theory, how 'bout 'Merman' comes from a fish who accidently ate a demon fruit?
it's no diffrent like chopper right? we didn't even know what fruit did he ate?
in manga and anime says that he ate 'hito-hito' fruit means human fruit. we even don't know waht will hapen if human eats human fruit?
like 'Feanor' says "If Oda decides that something like that exists, than he has to counter-balance it"

HOw bout this?

1. human + devil fruit(Zoan type) = human animal (Peru,lucchi, etc) ->can't swim
2. animal + devil fruit(Zoan type) = animal human(chopper) -> can't swim
3. fish + devil fruit(Zoan type) = Merman -> Maybe, they can't last long in land, so that explain why Arlong troops have the big swimming pool in his park!

:-D