Treating cyanobacteria (blue-green or slimy algae).

[shawmutt]

OK, as a result of my overfeeding a while ago, I now have a bad case of (I think) cyanobacteria. It's dark green, grows really fast, and coats everything in sheets that peel right off. I have corrected the overfeeding problem, and my nitrates are really low (>10 ppm) but the cyano is not going away. Also, I use only r/o water in my tanks, so there's no unwanted food going in the tank. My other tank has had it for quite a while, but since I clean it once a week I never really realized it was a problem--I thought it was normal to have a green tank in a week . Now that I recognize the problem I want to get rid of it.

From the research I have done, I found a drug called Erythromycin. Apparently tricks for algea, such as darkening the tank for 48 hours, water changes galore, and/or reduced feeding will not work--becuase this is not algea. Two questions:

Does it sound like I do, in fact, have a cyano problem?

(In three parts )Has anyone else used Erythromycin or another antibiotic in their tank? Any bad results/good results? Would you recommend the treatment?

 

[Fruitbat]

Shawmutt.....
1) Yes....it sounds like you have a cyanobacteria (probably Oscillatoria) problem
2) Haven't used erythromycin but I suppose it might work.

Darkening the tank probably won't work because, although the cyanobacteria are photosynthetic, they don't need much light to survive. You can remove the stuff from your tanks by hand but you'll probably leave enough for it to start all over again as soon as conditions are right. Only goldfish will eat it.

 

[Madame_X]

The cyano actually responds really well to a black out. I had it in my tank (courtesy of some Petsmart cabomba... :x ) and the black-out really helped.

I ended up treating with Maracyn anyway because I could still smell the stuff and I figured it would come back. It hasn't returned since the Maracyn (erythromycin) treatment.

I would suggest a combination of the two if the cyano is really bad. The drawback with the antibiotic treatment is that it can kill off your bio-filter. Of course, the box says that it won't but its still a risk. It wasn't a big problem for me as my tank is heavily planted, but if I remember correctly you have a cichlid tank so probably no plants. Just be very watchful of your water parameters if you do the antibiotic treatment.

Good luck!

 

[Sinuhe]

If you only have a slight case, it might be enough to syphon out all you can with frequent water changes. That worked for one of my tanks, and I haven't seen any for weeks. My QT tank has a pretty bad case of it. I'll probably strip down the whole tank, or use an antibiotic after I'm done QT'ing my fish.

A question: is cyanobacteria harmful to the fish? The fish in my QT don't seem to mind it at all.

 

[shawmutt]

A question: is cyanobacteria harmful to the fish? The fish in my QT don't seem to mind it at all.

It's not harmful to fish, per se, but now that I recognize what it is I am obsessed with eradicating the problem.

I have ottos in my 10 gallon (I know, it's stuffed to the brim) and I have had to supplement their diet with algea wafers because the cyano prevents healthy algae from growing. It coats my plants quickly (within a day or two) and is stunting their growth.

My 30 gallon isn't so bad, but I'm losing a lot of sand every week because the stuff sheets over my sand substrate and I have to vacuum it off. It seems to be growing faster every week. Plus I'm trying to grow a really cool algea mat like I saw in a cichlid tank in my lfs. That's actually how I found I had such a problem--I thought I was well on my way to growing an algae mat until I saw the one at the lfs. I came home and was like, wait a second...that's not algae...DOH!

I bought the erythromycin today at PetSmart, it's called Maracyn from Virbac. There were two types, Maracyn and Maracyn-Two. I checked the ingredients, and the Maracyn has 200mg erythromycin. It was expensive, $6.99 (American dollars) for 8 tabs. The next time I get it I'm going online. I'm doing my water change tonight, so I'm going to take out all my carbon and dose the tank.

 

[TankGirl]

I got rid of mine in my 10-gal with water changes every day for about a week or ten days, with removal by hand of whatever I could. It has not returned. I am definitely interested in hearing how the medication works. If you disturb your biofilter there is always BioSpira!

 

[shawmutt]

Just a quick update...I've been too busy cleaning and doing detective work on my 10 gallon to pay much mind to my 30 gallon. I have just put the last dose of a 5 day cycle of erythromycin in the tank. Aside from some weird foamy bubbles on the water's surface, there have been no side effects. The cyano is almost eradicated, I have none on my sand and very little left on the back glass panel. Tomorrow I will be doing a 30-40% water change and putting carbon in my canister filter. I actually see a bit of different algae in the tank, so good news as far as the 30 goes.

The only thing I would have done differently is ordered the erythromycin and carbon media online, I wound up paying a premium for them.

 

[Sinuhe]

Glad to hear it's getting better

I managed to get rid of a pretty bad case of cyanobacteria in my QT tank by performing about 3 vacuums per week, and keeping the lights off for most of the time for several days. Now the bad stuff is gone, and the tank looks good . I'm glad I didn't need medication that might mess something else up.