If you just purchased some new fish, we recommend using a trio of quarantine medications to treat any bacterial, fungal or parasitic diseases they may have. This is the same three broad-spectrum medicines that we use on all fish that enter the Aquarium Co-Op retail store. These medicines can all be used at the same time and are completely safe for all freshwater fish, shrimp, snails, and other invertebrates. Follow these dosing instructions:
- If you are treating new fish, make sure the quarantine tank is far away from your normal display tank, and do not let the tanks share any nets, siphons, buckets, or other equipment. Since droplets of water can travel on your hands to another aquarium, make sure to thoroughly wash your hands and arms with soap and hot water between tanks.
- If you are treating the entire display aquarium, do a thorough cleaning of the tank to make sure the fish’s environment is optimal and free of any stress factors before starting treatment. Wipe the aquarium walls so that you can easily observe the fish’s condition, clean out the waste in your filter, and use a siphon to vacuum the substrate and change the water.
- Remove any chemical filtration (such as activated carbon or Purigen), and turn off any UV sterilizers you may be using. Consider adding extra surface agitation (such as with a simple air stone and air pump), since some medications can change the water’s viscosity and hamper with the fish’s breathing ability.
- Do not dose according to the box instructions. Instead, add 1 packet of Maracyn, 1 packet of ParaCleanse, and 1 U.S. teaspoon of Ich-X for every 10 gallons of aquarium water. (Ich-X does not stain aquarium decorations in our experience, but be careful not to spill it because it can stain your skin or clothing.)
- Let the fish soak in the medication, and do not feed them or change any water for 1 week. (If you feel you must feed your fish, wait until Day 4 or 5, and then only feed them very lightly.) You should keep the aquarium filter and heater on during this time. Also, aquarium lighting will not deactivate the medication.
- After 1 week has passed, change out 30% of the water in the aquarium. Resume feeding the fish, keep the water quality high, and watch for any change in symptoms.
If you have very weak fish, it may be easier on their bodies to space out the treatment. Bacterial infections are the most common, so use Maracyn first for a week (at the dosage recommended in Step 4). Ich and external parasites are the second most common, so next treat the fish with Ich-X for a week. Internal worms and gill flukes are slower-acting pathogens, so dose ParaCleanse in the third week.
If you can clearly identify the illness that your fish has, only use the specific medication for that disease and following the dosing instructions on the package. Maracyn treats bacterial infections, Ich-X treats fungal infections and some external parasites, and ParaCleanse treats internal and some external parasites.
For more information, read our full article on how to treat sick aquarium fish