Treating Bryopsis Algae in a Reef Aquarium Using Fluconazole

Treating Bryopsis Algae in a Reef Aquarium Using Fluconazole
Today we were out working on Matthew McMillan’s reef aquarium, carrying out a full bryopsis algae treatment using Fluconazole.
Bryopsis algae is one of the most frustrating nuisance algae problems in reef aquariums and marine tanks. It can quickly spread throughout live rock and coral systems, becoming difficult to control through manual removal alone.
One of the most effective reef-safe treatments we’ve used for bryopsis algae removal is Fluconazole.
What is Fluconazole?
Fluconazole is an antifungal medication traditionally used to treat fungal infections in fish and aquatic systems. In recent years, reef hobbyists have discovered that Fluconazole can also be highly effective at eliminating bryopsis algae and, in some cases, green hair algae in reef aquariums.
One of the biggest advantages of Fluconazole treatment is that it is generally considered reef safe when used correctly, meaning it typically does not harm:
- Corals

- Anemones

- Snails

- Hermit crabs

- Most reef-safe invertebrates
This makes it a popular option for reef aquarium algae control without needing to completely strip down the system.
Important Preparation Before Treatment
When treating bryopsis algae with Fluconazole, it’s important to remove or disable filtration methods that may absorb or remove the medication from the aquarium water.
During Treatment:
- Turn off protein skimmers for the first 3 days

  - Alternatively, remove the skimmer collection cup and allow the skimmer body to continue circulating water

- Remove activated carbon and chemical filtration media

- GFO can continue to run during treatment

- Monitor water quality closely throughout the process
GFO can actually help reduce phosphate spikes caused by dying algae during the treatment process.
Recommended Fluconazole Dosage for Bryopsis
The commonly recommended dosage is:
200mg of Fluconazole per 10 gallons of aquarium water
To dose:
1. Open the capsule and remove the powder

2. Dissolve the Fluconazole in a cup of aquarium water

3. Add the mixture into a high-flow area of the reef tank
Treatment is typically carried out over 14 days.
After the treatment period, perform a 30% water change and gradually return filtration systems back to normal operation.
Can Fluconazole Treat Hair Algae?
Fluconazole may also help with some forms of green hair algae in reef aquariums, although results can vary depending on the algae species and severity of the outbreak.
In some systems, treatment may need to be extended up to 28 days for stubborn algae issues.
Final Thoughts on Bryopsis Treatment
Bryopsis algae can be extremely difficult to eliminate in a saltwater aquarium, but Fluconazole has become one of the most effective reef-safe treatment methods currently used in the reef aquarium hobby.
As with any reef aquarium treatment, closely monitor:
- Nutrients

- Oxygen levels

- Water chemistry

- Coral behaviour

- Fish health
Every aquarium system is different, so proceed carefully and research thoroughly before treatment.
If you’re struggling with bryopsis algae, hair algae, or reef aquarium pest issues, Aquamarine Aquaristic can help with reef tank advice, coral care, and marine aquarium solutions Australia wide.