Raise the water temperature to 30 degrees, because your water already has bacteria, and the cat's skin will turn white and swell in a few days.
Change 1/4 water every day, and brush the cylinder when you have time. The cylinder is dirty. Don't use salt, cats can't get salt.
You can put some yellow powder in the jar, once every three days according to the instructions.
Clean and disinfect your troubles.
You don't have to stop eating and resting these days. It is a good cat. Enter this way. . . . . . . ?
Tell you again, the tail is bleeding. See the white on the small meat fin? That's the predecessor of water mold. The left and right oars have begun to grow white hairs.
Water temperature 30-32 degrees, yellow powder, or go to Taobao to find (I use universal fish medicine) brand to choose. That's all, remember to brush the cylinder!