Black Filament Algae/Fungus Problem

[DavidMM]

Hi Everyone. My wife and I are about 4 months into our Biocube 32. It was going well until about 6 weeks ago when this hairy black algae or fungus showed up. It's quite prolific. It will form a translucent mat on the sand bed and rocks and will start growing the hairy filaments. What you see in the pic is about 2 days after a thorough cleaning. We recently removed all the rock and scrubbed them, sifted the sand and scrubbed the tank walls. This seemed to help for about four days, but now it's back again. One LFS has no idea what it is and another says it's Red Cyanobacteria (which I tend to disagree with). We've tried to think back to anything we might have added to the tank other than the basic chemicals. We have a collection of sea shells and sea urchin skeletons that we've collected from the Caribbean. We put an urchin skeleton in the tank along with a few shells that were a little larger than the hermit crabs we have.
We've been dosing with Vibrant but other than making the water really clear, it's not helping with this stuff. We are considering ending the vibrant dosing and trying Chemiclean.

 

[reefrubble]

Hi DavidMM,

While the black color is a complete oddity, the way that it spreads out on live rock and sand along with the way that is forms dense stringy clusters leads me to believe that what you have here is Dynoflagellates. My next best inference would be that it is Diatoms, as they often behave this way as well and are known for often appearing with dark coloration.

But wait... Alas, I have found a thread with extremely similar pictures to the one you provided. In this thread they seam to believe that it is indeed Cyanobacteria, which I certainly would not rule out!

I have a 30gallon reef tank hooked up to a fluval 207 canister filter, as well as a surface slimmer and media reactor. I have had this black cyano looking stuff that is stringing and acts as a layer of slime over my sand. I have dosed the tank twice with Chemi-Clean however it only eliminated half of the bacteria and with in a day it all returned. Any recommendations ? It has already killed my zoas and killed my fish over night as I have read that they can be extremely toxic

If you want a conclusive answer, your best bet would be picking up an inexpensive microscope, adding a sample of it to a slide, and comparing what you see to microscopic pictures of different potential culprits that can be found easily online.

Drop a like if you found this helpful!

 

[homer1475]

100% cyanobacteria

While it is mostly red, cyano can come in any color imaginable.

Increasing flow to the area can help if that is the only spot it is in. While I typically never reccomend chemical treatments, chemiclean woul mop that up. Just be careful with it, some cyano can be toxic when it dies.

 

[DavidMM]

Thanks for the replies. I'm a big dummy because for the first 24 hours of the chemi clean treatment, I forgot to turn off the UV sterilizer. Needless to say, the whatever-it-is is still there, unfazed. I read through the thread about rip cleaning the tank. It sounds easy enough but my rocks are covered with this stuff. I'm afraid that even if I scrub them with a toothbrush, I won't be able to get it all off. I also have my corals glued to the rocks and I have a little bubble anemone living in one. This stuff is even on some of my snails. Again, if I can't get it all off, I'm afraid it will just end up coming back.