Many diseases can affect the fish in your aquarium if they are not properly cared for. In the case of diseases caused by an infection, you can use a natural product called tea tree oil, which has antibiotic properties, to help prevent these infections. For example, if you notice your fish have been fighting or nipping at each other, or that one of your fish has a torn fin, you can try using tea tree oil to keep them healthy. You can mix tea tree oil with the water, right in your aquarium.
Purchase a tea tree oil that contains at least a 30 percent level of Terpinen-4-ol (the main active ingredient in tea tree oil). This level indicates the amount of antimicrobial capability. Also make sure the amount of cineole (a substance found in many essential oils) in the tea tree oil is 15 percent or less. Anything higher than 15 percent can cause irritation to the fish's scales.
Place 1/8 of a teaspoon of tea tree oil in the aquarium for every gallon of water in your fish tank.
Mix the tree tea oil around slowly with a small fish net, until it is blended with the aquarium water.
To help prevent potential infections, repeat Steps 2 and 3 once a day for three days.