Strange algae

[Taelen]

Hey guys,

Haven't posted in a while, a new baby will do that!

I have some strange stuff in my 38g tank (I recently completed switching to black sand and real plants). I have checked out the algae resources but I have seen nothing quite like this, I can only describe it as a black velvet substance.

Tank parameters are all in check and the occupants are a golden gourami, a pearl gourami, a mountain minnow (I think), a striped raphael catfish and a BN pleco.

Anyone seen this before?

Thanks.

 

[fort384]

Are you sure it is not BBA run amuck? Here is a photo of a pretty bad BBA infestation. Picture might help the ID.

 

[Taelen]

I don't think so but I will take a pic and post it to confirm. It might be picking up some of the black sand, but it appears to be a lot thicker than BBA, almost carpet like.

 

[fort384]

Here is a pic of some really thick BBA... does it look anything like this?

 

[jsoong]

I have something like that black velvet as well. It started out as dark green, then turned black & form a thick sheet, but without the fuzzy edge like the BBA pictured. That stuff smothers plants & is stuck tight to the leaves & everything else.

My guess is that it is either BBA or BGA. However, it doesn't seem to be susceptible to Excel or H2O2. It is definitely light requiring, as blacking out for 5-6 days will get rid of it. Currently, I am controlling it with severe nutrient restriction .... basically let my hornwort run amok (to take up all nutrients) & not adding any ferts (except for weekly KNO3). Seems to be working, but I still get traces here & there.

 

[Taelen]

Ok, it's definitely not BBA.

I'm currently not dosing that tank with ferts and the lighting is around 2x 3700K on a 12 hour cycle. Maybe I should cut down to 8 hours or so.

Here is a link to the video, you can see it coating my java ferns, anubias and creeping up my hornwort and anacharis, as well as sitting on top of the substrate and driftwood. Yes, I know my aquascaping skills are horrible. =P

YouTube - Strange algae

 

[CHBGator]

Looks like Cyanobacteria. Remove as much as possible manually then do a 50% water change, blackout the tank for 3 days, don't let ANY light in and no feeding the fish for the 3 days then remove the blackout and do another 50% water change.

 

[Taelen]

Sounds good Gator, I'll try that...any idea as to the root cause so it won't return?

Also, I've never blacked out a tank before, fish will be ok for 3 days without food?

 

[fort384]

Taelen, BGA can be caused by a number of things... excess light, excess nutrients, not enough flow.

I had a little go around with it. I put a small power head in that keeps the floor of my aquarium moving a little better, and reduced the photperiod and that seemed to do the trick. I have not had it return in the past 2 months.

 

[Taelen]

Thanks Fort, I am doing a blackout now, afterwards I will cut down the light to about 8 hours and observe. =)