The Line at the Blue Rock

The water was warm as bathwater near the surface and cooler in the pockets where the reef dropped away. Maya floated face down, arms out, letting the small waves push her toward a blue-gray rock the size of a car. Soren floated a body length behind her, one hand holding the strap of his mask because it kept leaking.

Their aunt had gone back to the boat to fix a fin buckle. She had told them to stay where they could touch bottom. They could not touch bottom here. They both pretended not to have noticed.

At first the rock looked ordinary. Then Maya saw the line.

Fish were waiting. Not swimming past, not darting. Waiting. A fat brown grouper hung in the water with its mouth hanging open, completely still, tilted slightly on its side like a car with a flat tire. Behind it a slim silver fish hovered. Behind that, a spotted thing with a mouth full of teeth Maya did not like the look of.

She lifted her head out of the water. Soren, she said. Come look. There's a line.

He swam up beside her and put his face back down. For a while neither of them moved except to breathe through the snorkels, a slow wet rasp.

Two tiny fish were doing the work. They were no longer than Maya's thumb, striped blue and black, and they moved fast and busy around the giant grouper's open mouth. They went inside the mouth. They came out. They went in again, right past the teeth, over the gills, along the edges of the huge lazy body.

Soren lifted his head. That grouper eats fish, he said. That size, it eats fish exactly that size.

I know, Maya said.

So why isn't it eating them.

They watched. The little striped fish worked the grouper over from nose to tail, and the grouper held itself perfectly still, mouth propped open, gills flared, doing nothing a hunting fish should do. When the small ones finished, the grouper closed its mouth slowly, gave a lazy shrug of its whole body, and swam off into the blue. The silver fish moved up into its place and went still and opened its mouth.

They're taking turns, Maya said. The big ones are taking turns.

Soren pushed his leaking mask back against his face. He was counting. She could tell he was counting, because his hand tapped his own leg once for each fish that came and went. Six big fish came and waited and were cleaned and left, and not one of them ate the small striped ones, and the small striped ones went into six mouths full of teeth and came out every time.

Maya dove. She held her breath and kicked down until the pressure squeezed her ears, until she was almost level with the blue-gray rock, and there she hung and looked closely at what the little fish were eating. They were picking things off. Off the skin, off the gills, off the soft places. Tiny pale specks. They were pulling the specks loose and swallowing them.

She came up gasping and spat out the snorkel. They're eating the bugs, she said. Off the big fish. The little ones eat the bugs off the big ones.

Soren was quiet, watching a new arrival settle into the line, a fish with a hooked jaw and a bad-tempered face.

So the big fish gets clean, he said slowly. And the little fish gets fed. So nobody wants to break it.

The hook-jawed fish opened its mouth. The striped cleaner darted straight inside, right down onto the tongue, into the exact place where one bite would end it. And the big fish held still. It held still on purpose. Maya could see the effort of it, the way you can see a dog holding still for a splinter to come out.

That's the part, Maya said, and stopped.

What part.

It's not that it can't eat them. It's that it's not going to. It's waiting in line at the thing that could eat it, and it's fine, because everybody here knows the rule.

Soren turned his head in the water to look at her. Water dripped off his mask. Nobody told them the rule, he said. There's no aunt out here telling them the rule.

They both looked back down at the blue rock, at the line of predators hanging patient in the current, mouths open, trusting the smallest fish on the reef with the softest parts of themselves. There was no fence. There was no lifeguard. There was nothing holding the truce together except that it worked, and every fish on the reef had somehow arrived at the same answer without anyone in charge.

A new thought moved over Maya, cold and enormous, colder than the water in the deep pockets. This was not one strange rock. This reef ran for miles. And on reefs all over the warm belt of the world there were rocks like this one, thousands of them, blue stations where the eaters lined up like customers and waited their turn, an agreement that no one wrote and no one enforced and every single fish somehow kept.

How far does it go, she said.

Soren didn't answer. He had dove. She saw him kicking down toward the rock, one hand pressed to his leaking mask, going to count the specks himself.

Below him the grouper came back. It slid into the end of the line, tilted onto its side, and opened its enormous mouth wide, and waited.