The tropical setting is postcard perfect. A palm tree on a deserted white beach surrounded by turquoise water imprints itself on my mind as I roll backward off the boat in full scuba gear. Just six feet underwater a rich coral bed stretches out as I pass through clouds of multicolored reef fish. I’m following Alejandro Vagelli, a marine biologist from Rutgers University and director of the Center for Aquatic Sciences in the United States, as he zigzags over the reef.

A gesture from Vagelli, and there before us flitting effortlessly among the spines of a cluster of sea urchins is a group of tiny, exquisite fish, the largest about an inch long.

Here in Indonesia the tranquil bays of 34 small