Fluconazole killed macros and Mangrove?

[Half Vaped]

I used Fluconazole last year to treat the GHA infestation in my 150. After two doses, I haven't seen any Bryopsis return, but after a few months, GHA started growing again on some of the plastic parts of the tank, but all the rocks are still pretty much clean of GHA. I was pretty impressed how effective the treatment turned out to be.

Unfortunately, the treatment seems to have wiped out all the macroalgae in my refugium in the process. All the Caulerpa and Chaeto started melting away and my 2.5-year-old Mangove died within maybe three weeks after the second Fluconazole treatment. Bubble algae, on the other hand, seems to have been completely unaffected and even spiked in growth after treatment (probably from the death of competing algae). I dosed 200 mg per 10G.

Am I the only one this happened to? I haven't read about anybody else losing macros with Fluconazole, but it's the only explanation that makes sense. My Fluconazole was made in China, so I'm sure it's possible that it had some kind of contaminant. Just curious if others had the same experience.

[sde1500]

Interesting, not something I've heard happening either. I don't believe much is known about how it breaks down overtime in our systems, between your doses, did you do any large water change or run carbon? Could be that if you didn't, the double dose may have caused some harm.

When I dosed the first time I had some outbreaks of cyano and other stuff after the GHA die of because I didn't do anything to control nutrients, even took my skimmer offline. I recently did another round, this time dosed vinegar and ran the skimmer. Had excellent results as well but less cyano popped up because I controlled the nutrient spike from the die off better. I'd guess the bubble algae got a good feeding from the die off like you said.

[Half Vaped]

I dosed Fluconazole around early Fall/late Summer last year, so details are a little fuzzy. I removed all carbon and shut off the UV before the first dose. The skimmer went crazy even with it set to minimum after dosing, so I let the skimmate overflow back into the fuge. I kept dosing NOPOX like normal the whole time. The skimmer calmed down after maybe three days and I started collecting skimmate for removal.

About a week after the first dose, I did ~15% water change and added the second dose. Skimmer went nuts again, which I gradually dialed back in. Maybe three weeks or so after the second dose, after most of the GHA was gone, I did another ~15% WC, added carbon and switched on the UV.

Now that you mention it, I also had a cyano outbreak after the treatment, which I addressed a few months later using Chemiclean. And I had to bump my NOPOX dose from ~25 ml to ~30 ml a day. The side effects to the macros and the Mangrove could very well have been due to using nearly double the dose, but I've read others have success with no ill effects using about the same dosage. Which made me think there might be some contaminant in the meds.

Maybe someone out there that needs to get rid of Caulerpa in their display might try to reproduce my experiment by using 40 mg Fluconazole per gallon? Preferably some of the Chinese variety.

[FullBoreReefer]

I was one of the first few who dosed this stuff when it was first found. It’s been quite awhile now...no issues