Above the rock shoals at the bottom of a reef slope, three schools of fish met. On most days that they met, individuals among them fought. They brawled amongst themselves and between species. The battles intensified as mating seasons approached. Conflicts simmered for weeks and then flared up again. Grudges set in and were carried for generations.
On most evenings, each school went its separate way. The groupers swam to the seagrass beds to hunt for smaller fish. The goatfish split up and descended to the sandy substrates. They combed the bottom for snails, worms, and molluscs. The snappers dove to a cool, dark reef that lay on a slope below the higher one. They ate the shrimp, squids, and crabs as well as nibbled on the kelp.
After a night of eating, the fish met again in the heat of the day. All of them coveted the valleys of the reef slope. All of them took shelter in the clefts between corals when large predators swam by.
"Watch out for the groupers," said one goatfish to another as the schools of fish passed each other.
"There are only a few," replied her friend. "None of them are large enough to hunt us."
"Look at those teeth. They're violent."
The elder goatfish turned his eye to the outnumbered groupers. They looked tough, yes, but defensive. They were not swimming toward anyone with aggression. They were keeping their distance.
Since the two of them had drifted to the edge of their school, they swam in a wide arc. The path took them near a mixed school, which consisted of goatfish and snappers together. The bluestripe snappers were numerous and therefore intimidating to medium-sized predators. Goatfish were able to change the shading of their stripes from yellow to blue, so they liked to merge their schools with the snappers. That let them camouflage themselves. The snappers didn't always like it.
Abruptly, the elder goatfish turned inward to their school, away from the snappers. His companion thought about remaining where she was on the outskirts but she felt something was wrong. She veered inward a little, enough to stay close to her friend.
"Why did you turn us away?" she asked him. "Are you biased against the snappers? Then why not against the groupers as well?"
"Several of the snappers were dangerous. Couldn't you see that they were about to start fighting?" He flipped his body to face the great swarm. They could both see the conflict in progress. Two fish picked on a smaller one at the edge of the group. "Worse for us, we have not adopted the colors of the snappers. They would react to that."
The scramble continued as the mixed school of snappers and goatfish grew closer to the school of goatfish. The snapper who was on the losing side had been driven out. Unlike the goatfish, a snapper did not feel safe on its own. That one needed to find a way back in.
The elder goatfish took pity. He turned toward the swarm of snappers.
As he closed in, two snappers charged to meet him. Whether they really meant to attack him or whether they intended to finish their battle with one of their own, in a moment they had no other target. The beaten snapper darted behind the goatfish. Only the elder fish remained, calm and relentless. His caudal fin stroked the waters evenly with no hesitation.
One of the snappers charged him. He did not dodge, which forced the attacker to veer to one side or else risk collision with a fish of equal strength and size. The second snapper charged a moment after. This one was smaller but it was quick and aggressive. The goatfish barely had time to turn his head so that the blow struck him on the gill cover, not on his ribcage or a fin.
He stared at the snapper. It was not a gaze of aggression. The snapper backed up to launch another attack. But it hesitated, confused. It was prepared for a sparring match. It wasn't ready for fearlessness and calm.
"Our mistake, friend," said the other aggressive snapper, the one who had charged first but veered off.
"Thank you, friend," said the goatfish.
All four of them rejoined their schools. The snappers darted quickly into their places. The elder goatfish took his time. His companion slowed to let him catch up to her. They swam side by side for a while near the outside of their school.
"Why didn't you fight back?" she asked him. "I don't understand what happened. When you didn't strike at them, why did the others stop attacking?"
"It does not always work that way," he drawled.
"That doesn't answer my question."
He kept up his pace. "Young one, do you think I am a goatfish?"
"Yes." But she paused to check for the barbs protruding from his chin. For a moment, he had seemed different.
"I don't feel that way." The movement of his caudal fin stayed strong and regular. "I belong to the race of peace keepers."
"Who are they?" She thought it sounded like a military order.
"We range all over the world. Those who don't know us think we belong to different schools and tribes. But we are the greatest tribe of all, the largest majority."
"That's not a tribe, then." It took her a long time to come to the conclusion. "Anyone can join."
"Yes. Anyone does. Eventually, I believe we will win over everyone."