I know what hybrid it is liao.
it's an extremely rare hybrid of Chaetodon tinkeri and Chaetodon milliaris.
In Hawaii, tinkeri will VERY rarely hybridise with miliaris. I've read about this hybridisation in my angel book and on certain websites. it's very rare and no pictures so far.
if you look at the photos of tinkeri and miliaris, you will see that the hybrid has both parent's features. the spots, the shape, etc.
so amazing that two completely diff butterflies from diff subgenus can hybridise.
there's also one featured in waikiki aquarium.