How to create a hospital tank? (fish aquarium)

Select a tank of about 38 liters and fill it with unchlorinated water. Fill two 10 liters containers with water similar to that in your fish tank. Now move the fish to the first container using a net. Gradually add salt in the proper proportion to the water for 10 minutes. Then shift the fish to the next container and let it stay there for about 45 minutes. After 20 minutes add salt in the same proportion to the water in the container holding the fish. Now, move the fish to the hospital tank and change the water daily.Shift the fish to the main tank only after it recovers completely.