Brown Jelly Disease: Causes & Treatment 

Sometimes things go smoothly in your aquarium, and then “bam” just like that, you have a brown jelly disease outbreak. The victims of this nasty disease are usually corals from the Euphyllia group.

Euphyllia Corals include some of our favorite LPS corals: Torches, Frogspawns, and Hammer Corals. They are without a doubt one of the most beautiful corals to add to reef aquariums, and their popularity means they will continue to dominate hobbyist’s tanks around the world. Their popularity comes from their fleshy polyps, vibrant color morphs, rapid growth, and hardiness.

Unfortunately, keeping Euphyllia Corals does come with one warning, and that is brown jelly disease.

What Causes Brown Jelly Disease?

Brown jelly disease is an issue that many hobbyists who have Euphyllia are likely to run into. Like most coral diseases, the cause of pathogen infections like brown jelly disease is still unknown. However, microscopic examination of coral tissues that were infected by brown jelly had numerous ciliates called Helicostoma nonatum

Even though we know there are ciliates present in the brown jelly mucus, scientists have still not determined what role they play in the disease. Because there are so many microbes present within the slime, it is hard to say which ciliate causes the infection. It is also still unclear if the ciliates are primary pathogens or secondary opportunists in brown jelly infections. But, there is increasing evidence that motile ciliates do play a role in coral diseases and opportunistic ciliates are not helping your Euphyllia survive the disease.

When it comes to causes of diseases on a hobbyist level, we can only come up with assumptions based on experience. Many hobbyists have found that poor water conditions, overfeeding, and damaged tissues can contribute to brown jelly infections, however, this is only “hear-say” and not scientifically proven yet. 

What Does Brown Jelly Disease Look Like & How To Spot It Early

If your coral is covered in a brown, gelatinous mass (like a slime or jelly-like “goo” substance) that is covering your coral’s flesh, it is likely you have a brown jelly outbreak. 

The brown jelly is associated with rapid tissue loss (RTS), which very quickly spreads to neighboring corals, regardless of the species. Because of the high contagion rates of RTS, once a coral is infected, you must act fast otherwise it will quickly deteriorate and die. 

If you take a close look at your infected coral, you will notice this brown jelly-like substance floating on the surface of your coral, moving around as your coral’s polyps sway with the water flow. The brown substance is also sometimes associated with a rotten smell once the coral has been removed from the aquarium. 

Spotting brown jelly disease early will determine if treatment is possible. As an aquarium hobbyist, it is important to check individual corals on a daily basis, so you can catch infections such as brown jelly before it overrules your aquarium. 

Treatment For Brown Jelly Disease

Depending on how bad the brown jelly infection is, will determine which treatment is best. Many hobbyists have had success with different treatment methods, however, do not be too hard on yourself if you try them yourselves, and they do not work. Brown jelly disease is a very difficult infection to treat because we do not know the cause. 

Many reef hobbyists have tried treating infected Euphyllia Corals affected by brown jelly disease outbreaks with different coral dips, but many have not succeeded and would agree that the best option is to frag off the infected area and throw it away. This can be a very hard decision to make, and trust me, I feel your pain, but a coral that is “too far gone” is better thrown away, than spreading the infection to all your other corals. 

Siphon Removal 

You can try to physically remove the brown jelly with a pipette or turkey baster around the infected areas (head). This must be done very carefully, so you do not smother your other corals, therefore it is recommended to remove your infected coral and treat it in a separate tank or container. 

If you must treat your coral inside an aquarium and cannot remove the coral, turn off all water flow. Take a pipette (or turkey baster) and siphon off the dead tissue and “goo” covering your infected coral. 

It is highly recommended, however, that you treat your coral outside the main aquarium. When removing an infected coral head, turn off any water flow, so the jelly is not blasted around the aquarium. When removing your coral, also make sure you wear gloves as some corals in your aquarium may contain toxins like palytoxin which is extremely harmful if it gets into your bloodstream. 

It is also recommended to frag heavily infected sections to reduce the spread and then continue treatment with a coral dip. 

Coral Dips & Antibiotics

Dipping a coral infected with brown jelly disease will hopefully eliminate the infection. 

There are different kinds of coral dips that you can try, but the best to treat fungal, bacterial, and microbial infections are iodine-based dips such as Seachem’s Reef Dip, or potassium-salt-based coral conditioners like Polyp Lab’s Reef Primer

Coral Dip: Seachem’s Reef Dip 

This Reef Dip must never be added directly into your reef aquarium, so set up a separate container to dip your infected coral. 

  • Per 4 L of aquarium water, add 1-2 caps (5-10 ml) of Reef Dip and mix thoroughly.
  • Dip your infected coral for 15-30 minutes.
  • Remove your coral from the dip and place it back into the aquarium.

Coral Dip: Polyp Lab’s Reef Primer 

Reef Primer must never be added directly into your reef aquarium, so set up a separate container to dip your infected coral. 

  • Per 4 L of aquarium water, add 8 caps (or 45 g) of Reef Primer and mix thoroughly. 
  • Dip your infected coral for a maximum of 5 minutes. 
  • Remove your coral from the dip and place it back into the aquarium.


Just like how you would use antibiotics to fight infections, antibiotics can also be used to treat brown jelly disease, and hopefully, give your coral a fighting chance to survive.

Many hobbyists have been successful in using Ciprofloxacin because it is still very effective in low doses, minimizing damage from dipping. It is recommended to use 0.125 mg/L of Ciprofloxacin by dissolving a 500 mg tablet in 50 ml of reverse osmosis deionized (RODI) water. 

Per 260 L of aquarium water, add 3.3 ml of the mixed antibiotic solution. Repeat this for the next 2-3 days and check the coral’s condition. 


Brown jelly is a contagious disease that commonly infects Euphyllia Corals. The cause of this infection is still unknown, however, there are a few treatments that hobbyists have been successful with, which include siphoning the brown jelly and dipping the infected coral. 

In severe cases, the best solution is to discard the infected coral. Removing a coral that is infected with brown jelly disease will save the rest of your corals in the aquarium. 

We wish you all the best in saving your coral from brown jelly disease. If you have had any success with other methods of brown jelly treatment, we would love to hear all about it – leave a reply below!

  • Roy Lee

    I have an unhealthy obsession with reef keeping and maintaining successful tanks. If you haven't noticed from the website, I love everything related to saltwater tanks like coral, fish, and everything else in between. Lee Roy

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