The Butterflyfish/Butterfly Fish is the 2nd fish in Dragon Shrine. It is before the Sakura Fish and after the Mudskipper.
It is yellow. It has black stripes. It looks like a real yellow-black Butterflyfish swimming.
Update V1.6.0, 26 May 2013; by Gamenauts.
It is found at around 30m.
Copied from Ninja Fishing (Updated) Wiki.