CATDOLL : CATDOLL: Mandarin fish fry dropped neck

Lack of oxygen. The weather is getting warmer, and the fry are growing rapidly and need a lot of oxygen. Another possibility is that the fish are eating plankton.

Is it due to lack of oxygen? I also raise Zhenzheng Mandarin fish (just started this year). Now it is 7 cm long. I also use cement pool to raise it. I plan to use cement pool to raise it carefully. My small Mandarin fish are all with their spines upside down and their heads down and their tails up. They are so cute especially when they are hunting. QQ 274864689. Let's exchange experiences.