Reef Bryopsis Elimination Fluconazole Guide: Dosing and Recovery
Bryopsis is the algae that breaks reefkeepers. Pulling it tears the holdfast and seeds a dozen new tufts, herbivores spit it out, and a year of careful husbandry can be lost to a feathery green hairshirt before the next water change. Reef bryopsis fluconazole dosing remains the only consistently effective hobbyist treatment, and it works because the antifungal disrupts the algae’s cell wall biosynthesis without harming inverts or corals when done correctly. This protocol from Gensou Aquascaping at 5 Everton Park is the exact dose and recovery sequence we walk customers through.
Confirm It Is Actually Bryopsis
True bryopsis has a feathery, fern-like frond pattern with branches in pairs along a central stalk — never random. Hair algae lacks the geometric branching, and turf algae presents as short, dense mats. Fluconazole only works on bryopsis and a few green filamentous species; misidentifying turf wastes a 21-day treatment window.
Source the Right Compound
Pharmacist-grade fluconazole capsules at 150 mg work fine; the brand-name aquarium products use the same molecule. Singapore vets and some specialist pharmacies stock generic 150 mg capsules around SGD 8-15 each. Avoid suspensions or compounded creams — only the powder inside hard capsules dissolves predictably in saltwater.
Calculate Dose Accurately
The therapeutic dose is 40 mg per litre of net water volume. Net volume means display plus sump minus rock and sand displacement, typically 70-80 per cent of the rated tank size. A 200-litre rated tank usually holds 150 litres of water, requiring 6 grams (40 capsules of 150 mg). Pre-dissolve the powder in 500 mL of warm tank water and add slowly to the sump return area for even mixing.
Equipment Shutdowns Are Mandatory
Remove activated carbon, GFO, biopellets and any chemical media that adsorb organics. Disable the protein skimmer for the entire 14-21 day treatment — skimmers strip fluconazole from the water column within hours. Switch off UV sterilisers and ozone. Refugium light and circulation stay on. Replacement carbon, fresh GFO and a backup skimmer pump live in the water care and treatment range for the post-treatment restart.
The 14 to 21 Day Window
Visible bryopsis whitens and shrivels between days 7 and 12. Hold the dose without water changes through the full 14 days minimum, extending to 21 days for stubborn outbreaks. Do not top up with fresh saltwater during the window — only RODI replacement for evaporation. Fish, shrimp, snails, hermits and the full spectrum of corals tolerate fluconazole at therapeutic dose, though some sensitive xenia and clove polyps may close temporarily.
Algae Removal During Treatment
Once tufts visibly bleach, scrub them off with a toothbrush during a manual rockwork cleaning session. The holdfasts are dead at that point and the fragments will not seed new growth. Siphon the loose material out rather than letting it dissolve into nutrient. A turkey baster across rockwork dislodges the last softened pieces.
Post-Treatment Recovery
At day 21, perform a 25 per cent water change with freshly mixed saltwater, then re-install carbon and restart the skimmer. Run carbon for one full week to scrub residual fluconazole and any cellular debris. Test alkalinity and calcium daily for the first week — corals often consume aggressively once the medicated water clears, and skipping a dose now causes STN. A reliable salt mix and refractometer from the marine saltwater range matter most during this restart.
Why Bryopsis Returns and How to Stop It
Bryopsis loves elevated magnesium relative to calcium and abundant phosphate. After treatment, target magnesium at 1300-1380 ppm rather than the 1500+ ppm some dosing methods chase. Keep phosphate at 0.03-0.05 ppm with GFO or lanthanum chloride and feed a polyp food regime that does not coat rockwork. New live rock from a tank with bryopsis seeds an outbreak within weeks — quarantine new pieces in a separate tub for two weeks before introduction.
When Fluconazole Fails
Resistance is rare but documented. If the second round at day 35 fails to clear remaining tufts, escalate to manual removal under hydrogen peroxide spot dosing (10 mL of 3 per cent solution per 100 L for 10 minutes outside the tank on affected rocks). Always quarantine treated rocks for a fortnight before reintroduction.
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emilynakatani
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