Earlier I said that this year, we can only build a small circular canvas fish pond high-density circulating fish culture system. Today, I will talk about the gains and losses of the past month, and continue to discuss whether it can make money to raise fish in canvas fish ponds.
The picture above shows two circular canvas fish ponds with a diameter of 4 meters and a height of 1.4 meters. Each is filled with water that can hold 15 cubic meters.
The water inlet pipe is a 50-diameter PVC pipe, the water pump is a 70W high-flow pump, and the drain bottom pipe is a 75-diameter PVC pipe. The actual operation proves that this configuration is sufficient.
 
In the picture above, this is the main purification tank converted from the previous two fish tanks. The foam tanks on both sides of the shrimp tank have not been changed much, and the black shell shrimp continue to be raised in it. There are two filters installed at the drain outlet. After running for so long, it has no major effect. It is mainly used to filter fish manure and suspended solids. It is still qualified, but the price is a little expensive.
There are also three auxiliary purification ponds, which are also used in the previous fish ponds, so they are not specially pictured.
This is the aeration of the main purification tank, which is a bit rudimentary. An aeration pump costs more than 2,000 yuan, and a special aeration tank is also required. This investment is a bit painful, so it is useless.
Now let's talk about the experience of the canvas fish pond circulating fish farming system for a month. It is a little more fish farming experience about this canvas fish pond.
A fish pond kept ding mandarin fish and grass carp that had been raised for a long time last year. There are about 300 ding mandarin fish, one or two small ones and one three or two large ones; 8 grass carp with a size of eight taels or more, and more than 60 grass carp fry with a size of 10 cm.
It has been raised for a month, and the ding mandarin fish is growing very well. It is better than the commercial pellet feed to be fed with the self-prepared sinking pellet feed.
During the period, five 10 cm grass carp fry died. After inspection, there was no disease, but it was thin. I was very puzzled at the time, and I only guessed the reason a few days ago.
This canvas fish pond with duckweed is mainly used to raise crocodiles.
I bought 5,000 Hehua fry, and gave 500 as gifts. I didn't count. I estimated that it was almost the same. When I opened the bag, there were not many hangs, less than 100. In terms of survival, this online shopping is OK. Yu Miao's size is too small. The fry I bought were 2-4 cm, and they were all 2 cm. Seeing such a small fry, the first reaction at that time was: It's miserable, can you feed it?
Before the fry went into the pond, he immediately corrected the first design problem of the canvas fish pond: the fish toilet provided by the manufacturer had a large leak hole, and the fry could easily escape, so he hurriedly made a barbed wire cover by himself, and then raised the water depth. to 1.3 meters.
The week before was fine, the fry grew very fast;
The second week, it was fine, the fry grew faster;
In the third week, it started to hang up in batches. . . . . . It was so miserable that I cried, until a few days ago, I was still hanging fry in batches.
Now feeding these remaining fry, there are probably less than 3,000, and I regret to death, and the fry are still hanging one after another.