From the sentence "pomegranate tree in the canopy fish tank, Mr. fat dog and fat girl", you can hear how much the old Beijingers like to raise fish and dogs, and the rich and leisurely courtyard life raises dogs and girls fat.

In the late summer and early autumn, mosquitoes gradually became scarce, and the sound of Mr. Teach's reading was heard in the study.

Pull out a chaise longue and sit under a canopy full of purple grapes, peeling off a red pomegranate, the ripe pomegranate seeds bursting out with sweet juice between your lips and teeth.

The fat old dog lazily lay on the side of the recliner, licking his tongue from time to time.

The outer wall of the fish tank condenses fine water droplets due to the abundant water vapor, which slowly converge under the action of gravity, and then flow down the tank wall, wetting a piece of bluestone.

A pair of goldfish with bubbling eyes spit bubbles and play among the green lotus leaves.

The white and fat little girl was running happily in the courtyard.

From this time on, a good life is closely linked to pets.

People who are at home have cats.

Lively and outgoing people have dogs.

People who want to cultivate their sentiments and self-cultivation can raise fish.

Of course, the life of the Beijing courtyard is not something that ordinary people can enjoy, and there is no 100 million yuan that cannot be enjoyed.

In the old days, fish farming was basically extensive breeding, and there were not many things to be paid attention to, and the cold-water fish such as goldfish, grass goldfish and koi fish were very hardy, and even in winter, there was no need to go to great lengths to move the fish tank into the house.

In addition, the fish tank in the old Beijing courtyard is not only used for fish farming, but also plays a role in firefighting.

Now the greenhouse effect is serious, and it can't snow twice in the whole winter, but Beijing was quite cold in the past winter, and after winter, the water surface of the fish tank formed a thick layer of ice.

When the ice melts in the spring, you will be surprised to find that the goldfish in the tank are swimming with their heads and tails again, as if they have not been affected by the freezing of the fish tank at all.

With the development of the times and science and technology, extensive fish farming can no longer meet people's needs, because people want to raise goldfish, grass gold and koi fish other than fish, raise some more delicate, more delicate, rare, more colorful fish, at this time it is the turn of a variety of aquarium equipment to appear.

People who are a little more serious about fish farming will go to the fish market or buy some simple equipment online, such as heating rods, water pumps, filters and filter materials, and then buy some pellet feed to live, all of which add up to only fifty or sixty yuan, so that they can basically cope with at least half of the freshwater fish.

People who are more serious and know how to look up information on the Internet will add some nitrifying bacteria, commonly used fish medicines, and oxygen pumps, and change the water in the fish tank regularly, so that they can feed at least eighty percent of the freshwater fish.

But sea life is much more complicated than this, Wang Qian and Li Kun stared at the dazzling array of equipment.

It is impossible for Zhang Zi'an to take care of the entire aquarium alone, and Wang Qian and Li Kun must be in charge of daily affairs in normal times, so he pointed to these equipment and explained the purpose to them one by one.

"We know it's a filter, right?" they said, fiddling with one of the devices.

"Well, but do you know what kind of filter it is?" Zhang Zi'an asked rhetorically.

They looked embarrassed, "This ...... Isn't a filter just a filter? Put some grinding wheels and filter cotton or something in it, and you can filter out the fish feces. ”

Zhang Zi'an shook his head and smiled: "The filter is not that simple. In the equipment of fish farming, the most important thing is the filtration system, and the quality of the filtration system determines whether the fish in the fish tank can survive for a long time. ”

Filters are broadly divided into three categories, physical filtration, biological filtration, and auxiliary filtration.

Physical filtration is what Wang Qian and Li Kun said about filtering fish feces and uneaten food residues.

Secondary filtration, also known as the nitrogen recycling system, converts ammonia produced by the breakdown of fish feces into nitrate, which is virtually non-toxic to fish.

Auxiliary filtration, including protein skintifiers, ozone generators, calcium reactors, denitrifiers and ultraviolet germicidal lamps, etc.

Every time he said one, he pointed to the corresponding equipment and asked them to remember its appearance and name, so as not to be confused, and as for the purpose of each equipment, it was not too late to remember it slowly.

In addition to this, there are different kinds of lights, heating rods, hydrometers, various test strips, and miscellaneous things.

Not all of this equipment was mailed by Karl from Germany, many of which he bought online before returning home, and some of the inconsequential equipment did not need to be too high-end.

Wang Qian took out a hand-copied net from a packing box and asked in a puzzled voice: "Master, why don't you just buy a few hand-copied nets, why do you buy a box as soon as you buy them? Can you use up so many hand-copied nets? Do you mean that the seller refuses to sell only one, but only in boxes?"

Li Kun also felt the same way, and they all thought that such extravagance and waste were not in line with Zhang Zi'an's consistent style.

The size of this whole box of hand-copied nets is 100, divided into several colors.

"Not really. Zhang Zi'an shook his head and said, "I was about to remind you that if you need to fish out of the fish tank in the future, you must remember that each fish tank corresponds to a hand-copied net, and it must not be mixed, otherwise once the fish in a certain fish tank get sick, it will soon infect all the fish." ”

"Oh, it's like a syringe that can't be used repeatedly?" Li Kun suddenly said.

"Almost. Zhang Zi'an affirmed.

When you go to a fish market, fish shop or aquarium to buy ornamental fish, you will see a thriving scene in the fish tank, and when you see the owner smiling and counting the money, you will never think that the first thing many shopkeepers do when they open the door every morning is crying and throwing dead fish out...... The so-called only saw the thief eat meat, but did not see the thief beaten.

Fish disease has the characteristics of slow onset, long cycle, high infectivity, etc., basically waiting until the onset of the disease has returned to the heavens, so it is very important to prevent and isolate the source of infection in advance, and the mixed use of hand-copied nets is very important but often overlooked by a vector, many owners who open fish shops with hot minds are paying tens of thousands, hundreds of thousands of tuition fees before they are enlightened.

Karl had reminded him of this.

The first task assigned by Zhang Zi'an to Wang Qian and Li Kun today was to use self-adhesive label paper to label each hand-copied net with a serial number, from 1 to 100, so as to correspond to each aquarium one by one, and it must not be mixed.

They nodded in agreement.

"What else is there that I don't understand what it's for?" Zhang Zi'an asked again.

Wang Qian and Li Kun glanced at each other.

Zhang Zi'an felt that their expressions were a little strange, "What's the matter?" If you don't understand, just ask directly, don't pretend to understand." It doesn't matter if you don't understand, no one understands it at first. ”

"Master, we understand the truth...... they said, "but ......"

"But what? If you have any questions, just say it. Zhang Zi'an urged, "I have something to do in a while." ”

Li Kun took out a packaging box from behind him, "Master, you asked us to move the courier after sorting it out, but I really don't know what this thing is for...... We thought it was a mistake at first, but the recipient is indeed your name......"

He shuddered and pulled out a set of pale blue bikinis with a pitiful amount of fabric from the box and carried one in each hand.

"Master, can you tell us what you are doing when you buy this?"

Zhang Zi'an looked light-hearted, "Oh, I bought it and gave it away." ”

They said with tears in their eyes: "Don't lie to us, Master! Even if you are a women's clothing boss, we will not dislike you!"

"Damn, where did you think of it, I really gave it away!" Zhang Zi'an clarified almost desperately.

God knows how the brains of these two second-class goods grow!

"But you don't have a girlfriend, you don't have a wife, who are you going to give a bikini to?

Zhang Zi'an was speechless, he couldn't say that there was a mermaid in the bathtub, he gave it to her, right?

"This ...... Who am I going to give it to your?

"Collection?"

Wang Qian and Li Kun listened, and the eyes looking at him had upgraded from "perverted" to "big perverted......