[SVB3290]

I have small outbreak of BGA in my 55 gallon planted cichlid tank that I've been controlling with manual removal and decreased feedings (fry in tank). I think it came in on some plants that I only quarantined for 2 weeks. No sign of it today (during partial water change) but filter floss i replaced smells strongly of BGA.

 

[DJRansome]

Treat with erythromycin. IDK if that would be harmful to fry. What species and how small?

IME it is a warning sign in a planted that that one plant or more is not doing well. When plants languish they leak fluids into the water that nourish the BGA.

Once the BGA is gone courtesy of the erythromycin, you could try fertilizing more to perk up the plants. In my scenario the plants had used all the nitrates and needed supplementation. What are your nitrate readings?

 

[BC in SK]

Treat with erythromycin.

For what reason do you treat a supposed algae "problem" with a chemical additive?https://en.wikipedia.org/wiki/Erythromycin
What exactly is the problem? Aesthetics, or the health of the fish or aquarium?

 

[DJRansome]

Are you thinking the blue green algae reported by OP is not cyanobacteria? Or are you saying cyanobacteria is not harmful to the fish or aquarium?

 

[BC in SK]

Or are you saying cyanobacteria is not harmful to the fish or aquarium?

Pretty much.
It's a part of virtually every aquatic environment. It's even eaten by many of our cichlids in their wild habitat. Thing like aufwuchs usually has a very good part Blue-Green Algae. The most common algae in fish food is spirulina, a Blue-Green algae
It can be prone to a boom and bust cycle so I guess if it really takes over an aquarium, when it dies off, could hurt water quality. But unless it's really excessive, it's usually harmless and of benefit to an aquarium just like any other algae or plant.
If the OP can control it with some manual removal and little less feeding, I don't see the reason to start using a chemical additive. The chemical additive should be the very last resort in the case of a really excessive outbreak that is persistent over a long period of time. Even if the additive is supposedly safe for fish, it can have a harmful effect on the health of the entire aquarium. An aquarium is like a mini-ecosystem; has a delicate balance, and it's really not a good idea to be killing off bacteria and algae that are an integral part of the system.

 

[DJRansome]

I agree with not adding chemicals when possible.

Have you ever found a cause of BGA to be plants that need more fertilizer? For me the vallisneria grew so fast they used all the nitrate and then started to fail.

 

[BC in SK]

Have you ever found a cause of BGA to be plants that need more fertilizer? For me the vallisneria grew so fast they used all the nitrate and then started to fail.

Very low, or zero nitrate would be desirable for the fish. In the very least, it resembles the water parameters that our cichlids usually come from, in the wild.
If the vallisneria grow so fast, they should be pruned a lot more. Any plant has to be harvested, otherwise it will break down, use oxygen, and release it's nutrients back into the water.

 

[DJRansome]

Agree. Have you ever know BGA to grow when the plants are starting to break down?

 

[BC in SK]

Have you ever know BGA to grow when the plants are starting to break down?

I'm sure BGA could start growing, when plants start to break down. But plant that is breaking down really should be pruned, probably even before it starts to break down.
I've always kept cichlids that really don't work so well with plants. So planted tanks are an experiment in my past; really haven't kept plants since the early '80's. I wouldn't recall anything about BGA attacking plants, though certainly do recall BBA (Black Brush Algae) growing on plants. I grow BBA, much, much better today. Better lighting and way, way more water change. And I've often had BGA growing on top and attacking BBA. I have at least a small presence of BGA in all of my tanks, but my 15 gal. and 29 gal. occasionally get over run with it when I am not stocking an algae eater in the tank. Two days after introducing a CAE, and my 15 gal. is completely cleaned up of any visible BGA. IME, common pleco or CAE will eat up BGA. Not certain about larger adult BN plecos, but I know when BNs are small, they don't eat it or make a real dent in BGA. Now, it can depend on the surface; none of these plecos are likely to spend alot of time on the surface of a plant as they don't even spend much time on a plastic plants (and the larger they are the less likely).

 

[DJRansome]

For me it did not attack the plants...it grew mostly on the bottom.

Removing the plants solved the BGA problem.

Thanks!