This kind of small fish is generally not filtered, aerated or oxygenated. I wonder if you have. If yes, change 1/3 water every half month. If not, draw a small amount of water every day (mainly sucking out fish feces and residual bait) to make up! You can eat the general commercial bait (choose the appropriate bait according to the size of the fish mouth), once a day, subject to eating it in 5 minutes, and remove the residual bait!