A manta cleaning station at sunrise.

The mantas at Lankan are clockwork. They come in around dawn, hold over the cleaning bommie at twelve metres, and let the cleaner wrasse work them for forty minutes. The trick is being there before they are.

Our liveaboard had repositioned the night before. We were in the water at 0610 — full dark on the surface, ambient lamp from the dive deck, no one in the channel except us and one other crew with the same idea. We descended to fifteen metres and waited at the edge of the bommie, kneeling in the sand, lights off. The cleaner wrasse were already in position. Smart fish. They know the schedule.

The first manta came in at 0628. Wing-span maybe four metres. It made one pass overhead and circled back, slowed, hovered. The wrasse boiled out of the bommie. The manta opened its mouth and held still. We watched, breathing as quietly as we could. A second manta came in at 0635, a third at 0642. By 0700 there were five animals working the station and the morning sun was starting to make the channel light.

There is a particular kind of quiet you can have on a dive when no one in the group is moving. It is not silence — there are bubbles, the click of a regulator. It is something else: a held attention. We surfaced at 0728 with full tanks of nothing-said, and the breakfast on the boat was delayed because nobody was in a hurry.