[Spoilers] What i always wondered

[Black-Star]

So i always wondered what would happen if a fishman ate a devil fruit and then i saw Van Decken (i think that was his name) and he was able to use abilities but what does happen when he is in the water? He is a fishman so he could be able to breath and as a fishman he must be able to swim better than humans so does water even affect him? My first theory is that he must be able to swim and breath underwater
second theory is he can't swim but he can breath so he's stuck underwater until someone helps him

Which theory u guys think is true and please give me your opinions

 

[SpiderRider89]

Sounds reasonable to me... He can't move in water anymore but he can't drown lol

 

[Mugiwara]

he probably wont die, but he wont be able to move underwater either. He'll just sink to the bottom and be unable to move. Maybe till he starves to death,.

 

[aniwth0z]

he will be able to breath but he wont be able to move and then DIE

 

[Black-Star]

he probably wont die, but he wont be able to move underwater either. He'll just sink to the bottom and be unable to move. Maybe till he starves to death,.

can't he just eat the planktons or anything?
you know this guy

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[Haruno Hyuuga Yamanaka]

He would survive underwater, since his fishman-exclusive organs allow him to breathe underwater, but his DF powers wouldn't allow him to move, so... he would be stuck underwater. Basically, he just doesn't drown, it's like throwing a rock to the sea...