Why is this pyramid butterflyfish half black ?

[Hiroyuki Tanaka]

Hi,

I got a half-black Pyramid Butterflyfish two day ago. When I found it it was similarly colored and selected it to photograph in home.

It seems a hybrid with the relative, Hemitaurichthys zoster from the Indian Ocean but I have no idea whether or not the two species co-occur anywhere.

Any idea for this one ?

 

[Meloco14]

Hmm, I don't think I've ever seen one with the half black body. I have this picture of a regular one from Saipan. I don't know if that helps you or not.

 

[Hiroyuki Tanaka]

Thanks for the nice pic.

Watch my fish on the tail that is dark. It cannot be seen in polylepis or zoster but thompsoni, but thompsoni is not one parent even if it is a hybrid among the Hemitaurichthys spp.

It has not changed its coloration yet.

 

[Pavaphon]

Hiroyuki,

At first glance, I thought that it might be the hybrid between the two as you suggested. H. zoster and H.polylepis. Due to the curving of the black color in the dorsal fin part.

But as you says, the problem is that where did they co-exist? is there any place that they could met each other?