User blog comment:Kogath/Monster Hunter X Discussion/@comment-25083735-20150710192336/@comment-26421638-20150710193331

Agnaktor,  Nibelsnarf and (maybe) Kuarusepusu cannot Swim even if they Are Classefied as Leviathans...

Why Mr.Bubbles should be a Fanged Wyvern? Because he has fur? ^_~ Well, even Pokaradon have Fur and is not a Wyvern... But is classified as Leviathan...

And yes... Mr. Bubble can use water...

I'm not sure, but Akantor was Classified as Flying Wyvern because he have a body structure quite similar to Tigrex...

I'm pretty sure that Mr.Bubbles can Swim... We know that many Monsters can swim even if you cannot Se doing that in game (Zamtrios, Tidal Najarala, Cephadrome etc)