Blue Tang or Blue and Yellow Hippo Tang

I've asked some questions on here about Blue Tangs and gotten some responses referring to Hippo Tangs. I know they are closely related but from some different sites like liveaquaria.com and saltwaterfish.com they list them as different. Are they in fact two different species of the same genre, or are they just so similar that replying about a hippo tang would be the same response as to a Blue Tang. A little confused lol

Thanks guys,

-Ben;D

 

as far as i know theyre an entirely different fish with the only thing keeping them in common is being tangs and the things tangs do. If they send you a blue tang when you ask for a hippo tang, you would be a pretty pissed off customer..

 

i would consider them the same fish they have the same scientific name lol
Paracanthurus hepatus

edit: there just color variations.