This is phase #2 of the 80/20 Quarantine Method to treat saltwater fish diseases before introduction into your aquarium.  The treatment described here is specifically for Uronema and Brooklynella and is intended to be integrated alongside the basic 80/20 quarantine procedures described in Phase 1.  



What is Brook?

Brook is short for Brooklynella and is sometimes called "Clownfish Disease" because it is prolific among wild-caught clownfish.  It is a parasite that lives entirely on the skin of the fish and does not contain any particular life stage where it is not attached to the fish which does make it a bit easier to treat compared to Ich. 

It appears like white mucous or cobwebs surrounding the body of the fish and can be extremely deadly. The fish will display clinched fins, labored breathing, and abnormal swim patterns and once these symptoms are displayed, the odds of survival are relatively low so proactive treatment is ideal. 

Unlike Ich and Marine Velvet, Brook is not responsive to copper treatments and the most effective medication is 37% Formalin which adds some complexity to the protocols. 

Brooklynella on Clownfish
Uronema on Emporer Angelfish

What is Uronema?

Similar to Brook, Uronema is a direct-contact ciliate parasite meaning its life cycle occurs entirely on the fish itself. It is prolific among Chromis but can affect a variety of fish that are sensitive to shipping.  It shows up like red open sores on the fish and once the symptoms are displayed, the odds of recovery are extremely low.  This is exactly why proactive treatment is recommended. 

Just like Brooklynella, the most effective treatment for Uronema is 37% Formalin. There are other documented treatments for both Brooklynella and Uronema but based on the advice from Marine Collectors, Formalin is the most effective. In either case, these diseases are not as well understood as velvet or ich and treatments are not 100% effective. Regardless, the integration of a formalin dip into your quarantine protocol can be critical to the survival of your new fish and prevent these diseases from being introduced into your display aquarium. 

Formalin is toxic and can be hazardous to your health. Do your own research and be sure to take the necessary precautions should you decide a formalin treatment is the best choice for your new fish.

How To Use Formalin

Formalin is administered in the way of a 35-minute bath in clean saltwater medicated with 37% Formalin.  Looking back at Phase 1, the Formalin bath procedure should be integrated into your regular quarantine protocol in place of the initial freshwater dip (Formalin also kills Flukes).  Then subsequent Formalin baths should be administered every 3 days during the treatment period when performing water changes. You will also be sterilizing the QT tank with freshwater during the water changes to prevent the survival of parasites in between water changes. 

Dosage for Formalin Bath

  • 1ml of 37% Formalin per gallon of clean saltwater (no copper in the Formalin bath)
  • Place airstone in the bath to circulate the water and provide oxygen

1.  Prepare the Formalin bath and soak fish for 35 minutes before introduction into your copper medicated QT aquarium.

2. Upon each water change, remove the fish and prepare a new Formalin bath.  While the fish are soaking, empty the aquarium to perform a water change.

3. Sterilize the empty aquarium by filling it with freshwater, and let it sit for 10 minutes.  Drain the freshwater and physically wipe down all the surfaces inside the aquarium. 

4. Refill the QT tank with copper medicated saltwater. Remove fish from the Formalin bath and place them back into the QT tank.

5. Repeat this process every 3 days during your quarantine protocol to treat for Brooklynella and Uronema alongside marine velvet and Ich

Caveats and Stipulations to Brooklynella and Uronema Treatments

Quarantine in general can be stressful so if you are treating sensitive fish such as Fairy/Flasher Wrasses, it's not the best idea to treat with Copper Power and Formalin simultaneously as we described for the sake of added stress. Instead, you can complete Phase1 treatment as described without the Formalin baths.  After the 15-day protocol is complete, sterilize the aquarium or use a different aquarium to repeat the process without copper medication and integrate the formalin baths. That would create a 30-day quarantine protocol that is less stressful on the fish yet comprehensive. 

On the contrary, if your treating fish that are especially prone to Uronema or Brooklynella, performing the Formalin dips first may be the best approach. Then follow that with the 15-day copper treatment to treat for Marine Velvet and Ich thereafter. This is especially true if the fish is showing symptoms of the disease. 

Formalin is stressful (sometimes deadly) and not all fish will require a formalin bath.  If you don't feel the fish are at risk of exposure or prone to Brooklynella and Uronema, the Formalin treatment is probably not necessary.  In other words, all fish should go through the phase 1 treatment using Copper Power.  Integrating a Formalin bath is a more advanced technique and should only be used if you feel confident and feel the treatment is necessary. 

Alternative Treatments

As mentioned earlier, there are other documented treatments for Brook and Uronema.  Freshwater dips, Chloroquine phosphate, and even peroxide are all methods that have been used by hobbyists with anecdotal evidence of success. Based on the guidance of Marine Collectors, these treatments may or may not be effective but most certainly are not as effective as Formalin.  

Feeding Metronidazole for Uronema

Feeding fish with Metro is an alternative method of pushing Uronema out of the fish's intestinal tract and has been documented as being successful. This method is certainly less stressful than Formalin and an option should you need it. The process involves mixing metronidazole with frozen fish foods so the fish ingests the medication.  Seachem Metroplex and Focus are both used and following the instructions provided should achieve sufficient results.