I have a friend named Oakley, and when he emailed, my spam blocker apparently thought he was trying to sell me sunglasses. That’s why just last week I found in my junk mail the note Oakley sent in early August.

“We saw a pair of leaf scorpionfish at 3 tables,” he wrote. “At least I’m pretty sure that’s what they were based on my Googling. Really cool. I thought of you. Is this something common in Hawaii? Never saw one before.”

They are really cool, and yes, leaf scorpionfish are common in Hawaii, sometimes in water only inches deep. But that doesn’t mean we commonly see them. Most people don’t notice them, because they look like their namesake: a leaf. Oakley writes that the two he saw were black and looked like dead leaves drifting.

I’ve surely missed seeing countless leaf scorpionfish during my snorkeling excursions, because camouflage is their (and most scorpionfishes’) defense. But I did spot one several years ago on the North Shore.

I thought it was a yellowing leaf until I noticed that it didn’t move as it should when a wave passed in the 3-foot-deep water. When I looked closer, I saw a starry eye staring back at me and knew I had a treasure.

Leaf scorpionfish belong to a large family called scorpionfish, notorious for poking anglers, waders and aquarists with the fishes’ sharp back and side fins. The stings are memorable because many of the world’s 350 species are packing. Venom flows into the victim from glands at the base of the fins’ spines. Leaf scorpionfish have no such venom.

Hawaii hosts 28 kinds of scorpionfish, 11 found only in our waters. Leaf scorpionfish, though, are widespread throughout the Indian and Pacific oceans.

In most places, finding a leaf scorpionfish is a rare event, but not so in Hawaii. Look carefully, though. The longest these little beauties get is 4 inches, but most are only 2 inches.

Besides looking like decomposing leaves (the fish can be white, pink, red, yellow, black, brown, green or mottled), leaf scorpionfish are hard to spot because they collect tiny bits of algae and other marine growth on their skin.

When the outfit becomes burdensome, the fish molts. Shedding can occur up to twice a month and starts at the head. In less than a minute, the little leaf-fish is back to its true skin color and starts trying on new accessories.

My yellow leaf scorpionfish held still for pictures, but even when I caused it to hop, it always kept its face inward toward its coral head. This typical head-in pose of the species serves as another defense strategy.

I thanked Oakley for writing, and we made a promise to go snorkeling together soon before the north swell starts up.

I ordered sunglasses from him, too, but I’m still waiting.

Reach Susan Scott at susanscott.net.