Keep new fish in a quarantine tank with the same water quality as the main tank. When you start getting impatient, think about how much trouble it would be to treat the entire population for infection instead of just one fish. Place the tank against an inside wall away from windows, doors and heating systems to prevent drafts and sudden temperature changes. Maintain the water quality. Test the ammonia, nitrite and pH levels regularly with a special kit.
Chemical imbalances are a leading cause of sickness in fish.
Once the water quality is acceptable, use a special filtered siphon to change 20 percent of the water every 10 days. A pet store that sells fish should also sell test kits and siphons. Provide your fish with a diet of commercially prepared fish food. Store it in a cool, dry place for no more than a few months. Remove waste and uneaten food with a net every other day.