The longfin bannerfish, Heniochus acuminatus, are omnivorous saltwater fish that feed mostly on plankton and invertibrates. They can grow to 10 inches long, but I guess these two are still young since they're the same size as the damselfish. They are very similar to the moorish idol (Gil from Finding Nemo), differing visually by an extra stripe on the tail and more yellow on the sides of the idol.
The black stripes on these guys are actually black, with a touch of white on the forehead area for a highlight. The yellow fins are olive green topped with deco yellow and yellow ochre. The cheeks are lilac with metallic silver and white and the rest of the white areas are metallic silver. The eye is black with a small metallic gold ring around it. The long dorsal fin will remain untouched paper, which is why you can't see them very well. They took just over an hour.