Bluespine unicornfish

A bluespine unicornfish swims off the Big Island.
When I’m out snorkeling, some fish don’t seem at all bothered by my presence, continuing to go about their business. Others will dart away the moment I appear (nothing personal I hope). Bluespine unicornfish fall somewhere in between. Mostly when I see them they appear unconcerned, but the distance between us inexorably grows.

No prizes for deducing how they get their name.

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