Tom glided across the sand. Sunlight broke through the glass, scattering gold coins across the gravel. Daisy whispered from across the tank, 'Two new faces at the bar window. They're staying for good.' Tom's fins went still. The tank felt suddenly too large.
Tom led the newcomers toward the coral maze, flicking his tail to show off the shimmering passage. The two merfolk barely glanced at the branches. Instead, they hovered near the far wall, drawn to the low vibration of the filtration pipes. Tom's smile faded. He kicked up a cloud of sand.
Tom tapped the glass at the back of the tank. The sharp ring echoed through the water. He gestured wildly for the pair to follow. They looked at each other, then the female held up a weathered shell, pointing toward a dark crack in the stone behind the pipes. Tom's mouth opened, then closed.
Tom followed them through the narrow crack, squeezing past cold stone. Beyond, a hidden grotto opened—its ceiling dripping with bioluminescent algae that pulsed soft blue-green in the slow current. It was the most beautiful place Tom had ever seen.
The male pulled a rusted brass key from his belt. He turned it in a lock set into the grotto wall. Stone grinding against stone, a second opening appeared—a passage that led straight back to the main tank, near the bar's stage.
Tom's fins fluttered in rapid bursts. The couple described how they found the passage during their training, their voices overlapping with eager laughter. Tom listened, his mouth forming words he couldn't quite shape.
That evening, Tom glided to the front of the tank. Daisy was on one side, the couple on the other. Four of them caught the light as bar patrons pressed their faces to the glass. The grotto glowed faintly behind them—a secret the whole tank now shared.
Tom flicked his tail in a wide arc, sending a spiral of light through the water. Daisy matched his rhythm. The couple mirrored them both. The patrons cheered. The water around Tom felt exactly like home.
A little girl pressed her nose to the glass. 'Look, Mum! There are four of them now!' Tom turned and saw her. He smiled—a real one this time—and gave a small wave. She waved back, her eyes wide.
Later, when the bar was quiet and the last customer had gone, Tom drifted to the edge of the grotto. The bioluminescent algae pulsed its slow, steady rhythm. He thought about the key, and the crack, and the couple who had shown him the way home.