Hawaiian flagtails

Hawaiian flagtails and achilles tangs in shallow surging water
Hawaiian flagtails are night feeders, but by day they congregate in shallow areas with a lot of surge as a protection against predators. This shoal was swooshing back and forth in the company of several achilles tang.

In my attempts to identify what I see in the water, I use John P. Hoover’s book The Ultimate Guide to Hawaiian Reef Fishes, Sea Turtles, Dolphins, Whales, and Seals. His website is hawaiisfishes.com.