This is a flowery flounder. What do you mean, where? It’s right there, on that rock. Truth is, if you don’t see a flounder moving, then you’re not likely to see it at all. This one was in a shallow area, hopping from rock to rock, in dappled sunlight.
A couple of times I took my eye off it and it took a while to relocate it, even though I knew where it was. Look up for too long and it will flit to a different spot. Good luck finding it them.
I particularly liked it when this fish bent itself over a little ledge in the rock (below). Not just a flatfish then, but a bendy one, too.
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.