Keep the tank clean and change the water once a week. A clean tank will ensure your fish recovers properly from fin rot and prevent the development of fin rot in the future. Get into the habit of cleaning the tank regularly.[14]
If you have a one gallon tank, you should change the water every three days. A 2.5 gallon tank should be changed every four to five days and a 5 gallon tank should be changed every seven days.[15]
If your tank is uncycled, you should do a 100% water change every time you clean the tank. Wash all the tank accessories and the gravel as well.
Add aquarium salt to the water after every cleaning to keep the tank water healthy and monitor the pH of the tank so it is comfortable for your fish.