Chapter 2611: Four Major Domesticated Fish

Knowing that Guan Youde had once worked as a Zhuangjia, Chen Wuren pressed further about fish fry: "Brother Guan, I understand that Jiujiang's fish fry are all caught from the West River. Why not sell them directly to fish farmers for their ponds? What purpose does the Zhuangjia serve as middlemen?"

"The Old Gentleman thinks carefully," Guan Youde replied. "The fry caught by Dan households are impure—a jumble of every species imaginable. They cannot simply be mixed together in a pond, or I fear nothing would survive. The Zhuangjia's value lies in sorting the catch, keeping only grass carp, silver carp, bighead carp, and mud carp—what we call the Four Major Domesticated Fish."

The methods for separating fry were naturally trade secrets, passed down through Zhuangjia families for generations and guarded jealously from outsiders.

As a local man, Chen Wuren was familiar with the concept of the Four Major Domesticated Fish. Before the Tang Dynasty, fishermen had primarily raised carp. But when the Tang emperors took the surname Li—which sounded identical to the word for carp—the fish became a symbol of royalty, forbidden to catch or sell. Fishermen were forced to find new varieties. Grass carp, silver carp, and bighead carp became the standards. Unlike the Yangtze River basin, however, Jiujiang villagers didn't raise black carp. Instead, they raised mud carp—commonly called local mud carp—a variety unique to South China. By the early Ming Dynasty, the coordinated farming of these Four Major Domesticated Fish had already reached maturity.

"If my clan were to raise fish," Chen Wuren asked, "how many should we stock per mu of pond?"

Zhong Ji, who had been listening along, chuckled at such a basic question. "For every mu of pond: thirty grass carp, one hundred and twenty silver carp, fifty bighead carp, and over a thousand local mud carp."

"Why such a disparity with the mud carp?" This came from Lin Chengwen, the Tiandihui's promotion manager for the Guangzhou region. In his experience, Lingao did things quite differently.

"Brother, there's a saying: 'Mud carp cannot be raised,'" Zhong Ji explained. "They thrive in heat but struggle to survive winter. By autumn's end, barely one in ten remains. Yet if they don't overwinter, they won't fatten properly, and lean fish fetch poor prices."

"So the Four Major Domesticated Fish command different prices?" Chen Wuren asked.

"It varies somewhat year to year, but in general, bighead and silver carp fetch the highest prices because they grow easily without consuming grass. Mud carp are difficult to raise—they rarely reach even one jin in weight and must survive the winter cold to become fat. Grass carp require feeding, so they're the cheapest." Zhong Ji held up four fingers. "Four taels of silver per hundred jin for bighead and silver carp. Two taels for grass carp. One tael for mud carp."

"How much grass do grass carp consume?" Lin Chengwen asked.

"A hundred jin of grass daily for every hundred fish. Grass carp eat the vegetation directly, while bighead and silver carp feed on the dissolved nutrients, or even the grass carp's waste can fertilize them."

As a Tiandihui cadre, Lin Chengwen had worked with freshwater fish farming in Lingao and understood the science behind this arrangement. Silver carp and bighead carp were filter feeders, using their gills to strain plankton from the water. They also enjoyed bean cakes, wheat bran, and similar feeds. Since fertile waters bred more plankton, these species gravitated toward nutrient-rich areas and stayed active in the upper water column. Grass carp were herbivores, feeding primarily on vegetation but also consuming grains, bean cakes, silkworm pupae, and earthworms. They preferred to forage in the middle and lower depths. Mud carp, the smallest of the four, were omnivorous bottom-dwellers that consumed plant debris and humus from the pond floor.

The ecological logic was elegant. Food scraps and waste from grass carp in the middle depths became excellent nutrients for plankton, which then multiplied to feed the silver carp and bighead carp above. Meanwhile, mud carp performed the final cleanup of residues from all three layers. This arrangement prevented food waste and excess plankton from degrading water quality. As fish at different depths chased their food, they stirred the water, increasing dissolved oxygen throughout. The coordinated farming of the Four Major Domesticated Fish represented a major leap in agricultural technology—a remarkably efficient use of limited water resources.

"How would we transport summer fry back to Xiangshan after purchase?" Chen Wuren asked Zhong Ji.

"There are few Gengzhongjia in Xiangshan and not many fish markets, so the Old Gentleman would need to hire transport. For nearby destinations, we use larger fry; for distant ones, smaller. Those traveling by land carry two baskets on a shoulder pole, swaying as they walk to rock the baskets up and down. This agitates the water into waves, making the fish feel as if they're still in a pond. Every two or three li, they lower the baskets into a stream to exchange the water, which keeps the fish healthy."

He continued, "For water transport, we use specialized fry boats. Two waterwheels mounted alongside run day and night, continuously cycling fresh water through while draining the old. This way the fry stay healthy throughout the journey. Water routes from Jiujiang to Xiangshan are convenient enough. For a household of the Old Gentleman's standing, I'd recommend boats. If you book through me, I can arrange a fry boat to deliver directly to your township."

The investigation team had no actual intention of purchasing fish fry. Chen Wuren smiled noncommittally. "Summer fry season is still some time away. No rush. Once I return home and arrange for the dikes to be dug, I'll certainly seek out Brother Zhong."

"No matter. Even if we do no business, we can still part as friends."

Chen Wuren suddenly remembered an earlier question he'd neglected to pursue. He turned to Guan Youde. "Brother Guan, might I ask—how exactly are the fry of the Four Major Domesticated Fish separated?"

Seeing that Chen Wuren wasn't placing orders but merely fishing for trade secrets, Guan Youde felt a flicker of annoyance. Though his expression remained neutral, his tone grew noticeably cooler. "The Old Gentleman asks many questions. Fish fry are fine as needles—tens of millions in a single scoop. Only Jiujiang people can distinguish them. Piehua—Skimming Fry—is the skill that feeds us Zhuangjia. It has always been passed down within families, never taught to outsiders."

Chen Wuren had spent enough time in Lingao to develop the habit of asking questions whenever something puzzled him. Only now did he realize he'd overstepped. In traditional society, any skill with technical value was passed through family or master-disciple lineages—and typically only to males, lest daughters carry the knowledge to their husband's families upon marriage. Apprentices had to labor like beasts of burden for years before learning their craft, and masters invariably held something back. Otherwise, how else could the saying go: "Teach the apprentice, starve the master"?

But Lingao operated differently. Except for a few classified matters, which Senator didn't eagerly pour knowledge into the naturalized citizens under their guidance, worried they might not learn quickly enough? Whenever a Senator encountered a naturalized citizen who loved asking questions, they were thrilled—treating them like treasures. Comparing the two approaches, Chen Wuren couldn't help but sigh. The difference was staggering.

They wandered through the Fish Fry Market until the sun climbed overhead and the temperature rose with it. Guan Youde, whose health had always been fragile, began to flag. "Master Mo, I'm feeling somewhat weary—head spinning, mind foggy. I'll take my leave here and hope you'll forgive me."

Mo Yu had been stationed in Jiujiang for two years and knew Guan Youde wasn't exaggerating. He let him go without protest. After Guan Youde and Zhong Ji departed, Lin Chengwen turned to Chen Wuren. "Section Chief Chen, it's no great loss that we didn't learn the Skimming Fry technique. In the future, we'll rely on artificial breeding—eggs of different species separated from the very beginning. The whole sorting step becomes unnecessary. If they want to guard their secret, let them. They can take it to their graves."

Chen Wuren nodded. "True enough. Still, the Chief instructed us to investigate every aspect of Jiujiang Township's fish fry production. He must have his reasons. This matter may not be as simple to unravel as it seems."

Hearing that this came from the Chief himself, Mo Yu spoke up. "That's easy enough. Next time some foolish Zhuangjia falls into my hands, I'll make certain he explains everything clearly. Otherwise he won't be slipping away."

"Brother Mo," Chen Wuren cautioned, "the Senate has always governed by law. Extracting confessions through torture carries penalties."

"I appreciate the Section Chief's concern." Mo Yu's smile turned wolfish. "I can make them talk without laying a finger on them."

"Actually," Lin Chengwen interjected, "I once heard an agriculture ministry Chief explain the principle behind Skimming Fry. Essentially, it exploits how different species prefer different water depths. The rest is simply a matter of practiced skill." He elaborated: "Bighead carp typically float at the very top, silver carp occupy the middle, grass carp swim slightly lower, and mud carp stay near the bottom. After placing the fry in a bamboo basket and letting them swim for an hour or two, workers use a white-painted wooden paddle to gently stir the water, skimming fish out layer by layer from top to bottom."

Chen Wuren considered this. "There's always a gap between knowing the principle and executing it in practice. Don't forget—besides the Four Major Domesticated Fish, other species are mixed in. Some share the same water depth. And when fry are fine as needles, distinguishing them is no simple task."

Lin Chengwen shrugged. "It doesn't matter. It's a dying art regardless. Based on everything we've learned, Jiujiang's freshwater fish farming techniques aren't superior to ours—though they do represent the highest level among the natives."

"You're serious?" Mo Yu looked surprised. Though he'd followed the Senate from early days and knew they surpassed the locals in virtually everything, he hadn't expected them to hold technical advantages even in something as humble as raising fish.

"Absolutely," Lin Chengwen confirmed. "Take the stocking ratios for the Four Major Domesticated Fish. Lingao stocks at least one hundred grass carp per mu, with only five hundred mud carp. Here, they stock just thirty grass carp—which tells you they don't have sufficient fodder grass. Their thousand mud carp per mu shows they haven't mastered overwintering techniques for the species yet. But the biggest issue remains the dike-to-pond ratio..."

This piqued Mo Yu's curiosity. "What should the dike-to-pond ratio be?"

"There's no universal correct answer—only what's suitable for the circumstances." Lin Chengwen didn't keep him in suspense. "Lingao uses 'Six Waters, Four Dikes,' while here it's the reverse: 'Four Waters, Six Dikes.' They're not utilizing their fish ponds to full capacity. And from what I've observed, local ponds rarely exceed five mu, while Lingao's range from seven to ten. That said, 'Four Waters, Six Dikes' does suit their production methods. Since this is mulberry-dike fish-pond country, the sericulture industry shapes the fishery."

Mo Yu nodded thoughtfully. "That makes sense. Jiujiang's income comes primarily from fish fry, then sericulture, then rice, then longan, then taro. If pond area is small with more dikes than water, income naturally suffers. There's clearly room for improvement."

(End of Chapter)