# Blue-Green"algae" (Cyanobacteria)



## t2000kw (Jul 29, 2006)

We have some of that cyanobacteria in our goldfish tank, almost gone after last evening's second dose of erythromycin, 200 mg per 10 gallons. 

Some web sites (and the container it came in) recommend that antibiotic for 2 days. Some recommend 5 days.

My questions:

1. Should it all be gone completely before I stop dosing the tank?
2. What has been your experience with erythromycin and blue green "algae" ? (not really an algae)

Donald Hellen


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## MatPat (Mar 22, 2004)

I've never used E-mycin for BGA outbreaks so I can't be of much help there. I have found a 3 day blackout works just fine and is free 

As for the cause (which I know you didn't ask about) BGA is usually caused by low nitrates which may not be the case in a goldfish tank. It also appers in area of low water flow so increaseing your flow in these areas of the tank may prevent it from coming back.

You should be able to dos a search on APC to find out how long people dose their tanks with E-mycin. I'm pretty sure one of the mods, Trenac, has used E-mycin before. You may want to give her a PM and ask her about it.


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## Tonka (Mar 20, 2004)

You need to collect as much of the BGA as you can and then treat with the same regimine you'd use to treat bacterial infections in fish, specifically 250mg of erythromycin per 10 gallons, repeated again after 24 hours. Then, don't change your water for five days.

You then need to address the reasons why you got BGA. Angle your filter's outflow over the affected area. If you can't do this, you might think about investing in a small submersible pump or powerhead that you can attach tubing to. also, you need to get your nutrients under control.

I use an Eihem 1250 and blocked-end black tubing that I've cut lots of holes into and snake around the back and sides at the level of the substrate. I only get BGA where I still have dead spots, up front and center where I don't have the tubing!

The problem with using antibiotics is that they do affect the rest of the gram positive bacteria in your tank. After you stop the treatment, it takes a while (weeks) for your tank's stability to return. You're then subject to bacterial blooms and other weirdness.

So, reach for the antibiotics only as a last resort.....


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## t2000kw (Jul 29, 2006)

We've decided to do the 5-day treatment. There's about a 50-50 split on whether to do 2-day or a full 5-day treatment. I have plenty of the antibiotic so we won't run out. 

But maybe next time I can try the 2-day program. I already dosed the 3rd dose before I checked my messages. 

I am spreading the stuff around using a System One filter without the filter. Lots of water movement so it will even out the medicine. 

I can say that the cyanobacteria has faded quite a bit already. Not all gone, though. Let's hope it's gone by day 5.

And thanks for the input.

Don


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## t2000kw (Jul 29, 2006)

Tonka said:


> You then need to address the reasons why you got BGA. Angle your filter's outflow over the affected area. If you can't do this, you might think about investing in a small submersible pump or powerhead that you can attach tubing to. also, you need to get your nutrients under control.


We have only recently increased circulation and added an air pump to address this, but it was after the problem started. It should help keep it from happening again, hopefully.

Don


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## Six (May 29, 2006)

Tonka said:


> So, reach for the antibiotics only as a last resort.....


i agree. also misuse of antibiotics aid in making more and more resiliant forms.

IMO, a little more tank maintenaince is all that is needed. Or ditch the goldfish, they are not easy fish aquariums to maintain. i'm sure you have them for a kid or something, but when you can "upgrade" to something that produces less waste and needs less work, do it.

gl


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## t2000kw (Jul 29, 2006)

It's not a matter of upgrading to other fish. We've had some of these for over 16 years with no problems, so this is an anomaly in the stream of time. Based on past experience, it's not real likely to occur again as long as we do more frequent water changes. These are Fancy goldfish (only one is a common "comet"), something that many people would kill to be able to keep so long and so healthy.

We also have angel fish and discus, neon tetras, cherry shrimp that are having a blast reproducing in another tank, and many others, too.

We generally have the ammonia/nitrates/nitrites under control, despite the fact that many people find it difficult to keep a goldfish tank under control. So actually, it's a bit of a challenge, and we've found ourselves to be among the few who have set up a natural, low light, low-tech tank with plants and goldfish co-existing peacefully. Many think it's not possible.

We just want to make a small correction and get things back in order again. My wife fell sick and didn't keep up with tank maintenance as she normally does. If it happens again, I'll just take over for a while.



Six said:


> i agree. also misuse of antibiotics aid in making more and more resiliant forms.
> 
> IMO, a little more tank maintenaince is all that is needed. Or ditch the goldfish, they are not easy fish aquariums to maintain. i'm sure you have them for a kid or something, but when you can "upgrade" to something that produces less waste and needs less work, do it.
> 
> gl


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## t2000kw (Jul 29, 2006)

I forgot to mention that the plants have cut down on much of the maintenance, but some still needs to be done on occasion. Thanks to forums such as El Naturel and this group we've converted to ALL planted tanks.


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