ID black/green moss or lichen (looks like)

[Johny]

Hey, over the past couple weeks I noticed some dark green (now almost black) spots starting on most of my rocks and wood. I didn't think much of it, especially because I just had a little battle with diatoms. I noticed tonight that they are getting larger, darker and raised up a bit, like moss or lichen.

Both the rocks and wood are from a creek up a local canyon. I brought them home, soaked them over night in very hot water in the tub (I don't have a pot available to boil them in) and then scrubbed them very well with a wire brush. I then let them dry out for several days before introducing them to the tank. All this was in hopes of preventing the introduction of harmful microorganisms.

I have had them in my tank for about 6-8 weeks with no noticeable negative effects. My water parameters are fine and stable. pH~ 7.8 (as high as 8.2 out of the tap), ammonia 0, nitrites 0, nitrates 10-20 ppm ( so hard to tell the difference between those two sometimes). Lighting is a DIY setup, with 4 X 13 watt CFL's. I also have a DIY CO2 setup, and my lights are on about 12 hours a day.

I will attach several pictures. They are as close as I can get them. Mostly I am just curious what it is.
Thanks for the help in advance.

 

[Crepe]

Looks like cyano or something. Is it slimy? Fluffy? Or is just bumps.

 

[Johny]

Looks like cyano or something. Is it slimy? Fluffy? Or is just bumps.

Just ran my finger over it. It is velvety. Very soft and fluffy (for it's size). And VERY resilient. I couldn't rub it off with my finger tip.

 

[Crepe]

Nascent BBA/black beard algae. I would take them out and bleach dip them if I were you.

Use 20% diluted bleach and soak for like 20 minutes. Then soak in clean water with some dechlor overnight. That will kill the bba on the rock. How much light do you have in your tank?

 

[Johny]

I have 4 CFL's, all of them 13 watts. Its a DIY set up. That too much, or not enough?

 

[Crepe]

How large is the tank? Generally you're looking at too much light.

 

[Johny]

20 gal high. So too much light will let these things grow?

Also, I did a google image search of BBA and what I saw doesn't look to me like what I have in my tank. The stuff in my tank looks and feels very similar to the moss you might see on a large damp rock next to a creek or something.

 

[Crepe]

There are lots of species of BBA. The common name applies to any chlorophyll dense filamentous (it's black because it's so green) algae...I would say without CO2 that might be too much light. Just clean the rocks off and do some water changes and the problem might stay away.

 

[Johny]

Is it dangerous? Will it harm my fish? Plants? Aquarium?

Also, I am running CO2. It is a DIY set up and certainly could be improved, but I am running it.

 

[Crepe]

Hmm. Then it should be going away on its own after you eliminate it. It shows up with changing CO2 conditions more than anything else. It's not dangerous. Just from an aesthetic standpoint you could do without it. It can overrun slower growing plants at its worst though so keep that in mind.

 

[Johny]

Let me revise my "very resilient" statement. I pulled one of the smaller rocks out to get a better look and try and get a better picture. Just to be sure I scraped the rock with my finger nail and black stuff came off. I then scrubbed at it with my glass scrubber and a lot of it came right off. All the algae I have dealt with in the past came off with a gentle wipe of the finger. This takes a little more effort, but still comes off without too much effort. Here is a picture of the rock I scrubbed. It is the same one as one of the original pictures.

 

[Johny]

Hmm. Then it should be going away on its own after you eliminate it. It shows up with changing CO2 conditions more than anything else. It's not dangerous. Just from an aesthetic standpoint you could do without it. It can overrun slower growing plants at its worst though so keep that in mind.

I have been playing with the yeast/sugar recipe in my CO2 setup. The first couple mixtures I tried were putting out a lot of CO2 but burning out pretty quick. This mixture is putting out a bit less CO2 and I am hoping that it will last longer.

Thanks for all the help. I will keep an eye on it.

 

[aqua_chem]

I would like to second Crepe's assessments:

BBA
Too much light and/or
Not enough CO2/Inconsistent CO2

DIY CO2 is very inconsistent by nature, fluctuation with temperature, age, and whenever it darn well feels like it.


Also note that while excel or H2O2 applied directly will kill it, if you don't address the root, it'll keep coming back.