Pyramid Butterflyfish, Hemitaurichthys polylepis. Palau at Saies Tunnel April 21, 2024

What's going on here? The Pyramid Butterflyfish usually hangs out in large groups over the edge of the reef actively feeding on zooplankton making it difficult to get good close-up video of them. But at this site near Saies Tunnel, I found a group of these fish hovering over a Diploastrea coral for no apparent reason. At first I thought a cleaner fish or shrimp might be nearby, but I never saw one. Nearby I found a few individuals uncharacteristically "loitering" and easy to get close video shots. This individual seems to be respiring rapidly - perhaps. Other fish in the area were similarly easy to approach and I may post video of them too. Thanks to the Coral Reef Research Foundation.