Depending on the situation, the medication and what is on hand, there are a variety of methods to administer medication to a sick fish. The most common and easiest method is to treat the fish in the main tank. While this option may be more convenient, it may not be the best option. The reason is that the treatment being administered will, in fact, treat all the fish in the tank, including those that do not require treatment. On the other hand, if the disease being treated is Ich, then it is best to treat the tank to be sure all of the Ich is irradicated during its lengthy life cycle.

Another consideration when treating the tank is the use of charcoal. If charcoal is being used in the tank, it is best to remove it during treatment. Otherwise, the charcoal will diminish the effect of the medication. Snails or other inverts in the tank may be sensitive to the treatment being administered and may die as a result. The same applies to live plants, in addition to the threat to benificial bacteria in the aquarium. If at all possible or if the entire tank does not require treatment, the next best option is to use a quarantine or hospital tank.

Using a hospital tank is not as convenient and does incur an additional cost, compared to treating the main tank. In addition to the tank and hood, there is the cost of a heater, possibly a light, cover, thermometer, gravel, filter and probably some type of decoration to help the fish feel secure, such as plastic plants. Beyond the treatment, there is the choice of whether to keep a cycled tank available, plus, it may be necessary to break the tank down completely for cleaning when treatment is complete.

The benefit is that the fish can be treated away from the main fish poplulation, which reduces the risk of other fish becoming ill and from being medicated unnecessarily. The potential for medications affecting plants and snails or other invertabrates is no longer an issue. Again, quarantine requires that a cycled tank be available at the time of treatment, otherwise the fish will be under the stress of a cycling tank. While there are methods to hasten the cycling process (which will not be discussed here), the benefit is that a cycled tank will also be available to quarantine new fish before adding them to existing tanks. To be sure, it is best not to purchse new fish for quarantine when the hospital tank is being used to treat a sick fish.

Depending on the medication, it may be possible to make a bath or dip for the fish. For example, a higher level of salt may be used in a bath for a short period (until the fish shows signs of stress) than the amount of salt that would be added to a quarantine tank over time. While this solution may be best for some medications, it is necessary to catch the fish, treat it and return it to the tank, which creates stress for the fish each time it is treated. Similarly, treatments that are applied directly to the fish with a small (artists) brush or swab, require that the fish be caught first, again creating stress.

If the fish is still eating, one option is to mix the medication in the fish food. This works best if the fish is in quarantine, since other fish will not be competing for the medicated food. The process requires moistening the food either with the medication and/or tank water so that the medication is absorbed into the food. The problem here is ensuring that the fish is receiving the correct dose of medication.

Two other options are available for administering medication to fish, however, the assistance of a veteranarian is recommended. One option is injection and the other is to administer the medication by tube. Obviously, a person trained in such procedures minimizes the risk to the fish and ensures the treatment is administered correctly.

To summarize, the situation, the medication and what the hobbyist may have on hand or can afford will dictate the method of treating a fish for disease. While one method may be more convenient than another, it may not be the best option. Some options for treatment will require the assistance of a trained professional. The options discussed here are to aid in determining the best option for a hobbyist to treat a sick fish.

Jepson, L. (2004). Common fish diseases. Neptune City, NJ: T.F.H. Publications, Inc.