A number of drugs that are intended to cure pet fish of bacterial, fungal, and parasitic infections are available in many pet stores. However, the vast majority of these drugs have never been adequately tested on tropical fish or the pathogens they are intended to kill.

Furthermore, using them without first having an accurate diagnosis from a licensed veterinarian is unwise and may put your pet fish at risk. If you must use these compounds, here are some tips which can help.

• If at all possible, do not treat the entire aquarium or pond. Set up a separate “hospital aquarium” instead.
• Perform a 25 percent water change following each treatment. This should occur at least every 24 hours.
• Do not combine drugs or switch drugs frequently.
• Remove any carbon/charcoal filtration during the treatment (carbon will remove the drug from the water).
• Aerate the aquarium or pond well during any chemical treatment.
• Observe your fish closely during treatment for signs of distress, especially during the first hour or two. If they look very stressed, remove them to clean untreated water.
• ALWAYS test the water before beginning any treatment. Many disease problems can be corrected by simply improving the water quality of your aquarium or pond.