Bryopsis? GHA?

indigoze · Mar 21, 2025

Hi all, I have a new problem in my tank. Seems that there is always a new problem for me

This nasty algae has started to appear in multiple places. It's very firmly attached to the rocks and plugs and can't be pulled off only trimmed. Is it bryopsis or gha?

For my next question I'm leaning towards fluconazole to get rid of it, but I have a lot of macros that I don't want to kill. I see some people saying they're fine, others say they die. Other than the caulerpa I don't recall the name of them but you can see them in the pics.

The nuisance algae in question is visible in pic 1 on the zoas and in pic 3 on the rocks but clumps of it are all around the tank.

Advice please

Btw water tests are all good no spikes of anything.

JTP424 · Mar 21, 2025

I'd say bryopsis but close up images would help. I would remove the macros to ensure they survive

indigoze · Mar 22, 2025

Are the any critters that may eat the stuff? I have snails and an urchin but they don't seem interested in it.

indigoze · Apr 3, 2025

So I have added this fluconazole product https://a.co/d/02Aq9LC at the recommended dosage 4 days ago and I see zero change. If anything the zoa's are more covered than they already were. It said to use 1 pill per 10 gallons so I used 1.5 since it's almost a 20 and accounting for the rocks and sand. No effect on fish or inverts that I can tell. Should I add more or just wait?

I'm very uncomfortable having the carbon and purigen out of the system, as it has always had them since I started the tank back in October. Being testing water daily no changes. Also no effect on the caulerpa and a few sprigs of red macro of some kind that I couldn't remove. I placed all the other macros in a heated bucket with a pump and the old light I had when I started the tank. Also threw the carbon and purigen bag in there with them.

JonoH · Apr 3, 2025

Looks like you have both in some parts...

fish_collector · Apr 3, 2025

With a pic that lacks great detail and all, that sure does look like bryopsis. It's fern shaped and will grow in clumps and as you found out it is nearly impossible to pull it out. GHA on the other hand usually does not grow in clumps, it will grow like grass in larger areas that face the light. Fluconazole will kill bryopsis but it takes a few weeks. It is somewhat effective on GHA but the dose needs to be higher and you have to leave it in the system for longer, weeks and weeks for sure, and leave the carbon out for the duration you want the fluconazole to stay active. It is ok to redose it after a few weeks. When you put the carbon back in use 1/3 or 1/2 as much so the zoas aren't light shocked, carbon will clear up yellowed water almost overnight.

I just did a fluconazole treatment in my fowlr to try and clear out some stubborn GHA. It was partially effective. What I have found is the newest GHA doesn't attach as well as it used to and is fairly easy to siphon out. I'm thinking another treatment may be necessary to eliminate it completely. It was great for a while though, I had literally nothing that grew on the glass for at least a month :face-with-tears-of-joy:

indigoze · Apr 3, 2025

So I simply wasn't patient enough lol. Today the patches of whatever algae they are, aren't looking well at all. No longer plump and bushy, but limp or collapsing and quite pale at the ends. This has progressed throughout the day and they look positively terminal now

I even saw a few pieces detach and float away sucked into the filter. Still zero effect on my overgrown caulerpa which I'm ok with. Pic 1 is this morning and Pic 2 is a minute ago. Please excuse my goby photo bombing. He thinks I'm gonna feed again.

painter1982 · Sep 28, 2025

indigoze said:
So I simply wasn't patient enough lol. Today the patches of whatever algae they are, aren't looking well at all. No longer plump and bushy, but limp or collapsing and quite pale at the ends. This has progressed throughout the day and they look positively terminal now I even saw a few pieces detach and float away sucked into the filter. Still zero effect on my overgrown caulerpa which I'm ok with. Pic 1 is this morning and Pic 2 is a minute ago. Please excuse my goby photo bombing. He thinks I'm gonna feed again.

How did this end? Any harm to corals? Did the bryopsis go away permanently?