Like clockwork, the cycle began once the first signs of warm weather came. Cyrus felt the stirrings beginning at the base of his tail, the tell-tale pressure that pushed him to find a mate to fertilize his eggs. It told him to swim toward land, where the largest shoals of fish would congregate to feed him and his inevitable young. This took days, though. Exhausting days full of swimming and little else. The whole time he swam, his body effortlessly produced eggs. Not all of them would grow but it didn't stop his belly from swelling until his tail and abdomen looked as round as a goldfish.
The night he finally reached the shoals, he was near ready to let the waves carry him away. His opening had swollen until it was puffy and dripping with fluid that drifted off into the water behind him. Each push of his tail rubbed his sensitive walls together and drove him crazy. He couldn't touch himself, though. Instinct kept him going and kept his hands off his sensitive flesh until he could lay his eggs.
Already, hundreds of others had come to hunt and breed among the rocks. He gave himself a few rubs to hopefully attract another male to swim down with him, then dove for his familiar resting spot. He eyed a few larger mermen who seemed to have caught his scent and followed eagerly. Before any of them could get to him, though, he slipped between the rocks and barred passage with his body. The message was received well enough. They would need to fight for him.
Not all layers forced potential mates to fight. Some would roll over and let anyone bully their egg sacs open to fertilize them, others chose based on whatever basis they felt like that season. Cyrus preferred to watch males fight over him.
There were three that had followed him down to the opening: a shiny silver male, smaller than the rest and clearly younger; a red male with yellow speckling all down his tail who was slow, but clearly strong; and last but not least, a blue male who had already begun to go after his competition. This would be fun. He turned his pelvis to present his swollen hole as an incentive and gave it a few strokes with his fingers to relieve himself.
While he lay in wait, the fight began. The blue and red mermen had begun to exchange bites but the silver one was smarter. He dodged the blows of his competitors while dashing in and out to tear into their fins. It was only when he razed the gills of one of the other males that they took notice of his strategy. Blue shoved him down into the sand and started to scrabble at his throat while he thrashed. The water clouded temporarily, giving Cyrus little more than flashes of color. He saw red, blue, and then there was gold in the water as blood was properly drawn. He grinned.