Cyanobacteria (aka BGA)

Hi Everyone,

For the last few weeks, I have been probing deeply into that potential menace in our tanks - BGA (Blue-Green Algae). As many people will be aware, BGA does not belong to the algae family at all. In fact, it's a type of bacteria masquerading as algae. Its correct name is Cyanobacteria. I could not ignore this stuff any longer. Some people will remember that I kept German Blue Rams (GBRs) and Panda Garras. A few months ago, I lost them all in the space of a few days. My investigation as to the cause of their sudden death has led me to BGA, of which some species can be very toxic.

I currently have an experimental tank running in which there are no fish. But, there was a significant amount of BGA in there at the outset. I have read numerous scientific research papers about cyanobacteria and some of it is understandable to someone (me!) who is not a microbiologist!

I hope to provide some more detail tomorrow.

JPC

Hi JPC,  I, and I'm sure everyone else too, read this as an interesting investigation that was underway and thus were awaiting the further detail that you had hoped to provide the following day, after which I'm quite sure replies/comments would have followed.

Hi Folks,

I'll try to keep things simple. Several months ago, I looked into my community tank to find my German Blue Rams (GBRs x 6) and Panda Garras (x2) sitting on the substrate barely moving. Their bodies had darkened and it looked as if they were paralyzed. It was a sorry sight. Just a few days before, they were full of life. What had happened? All the other fish - Cardinal Tetras, Otocinclus, Siamese Algae Eater, Pygmy Corydoras, C. habrosus were absolutely fine. This tended to rule out water parameters. Then, I remembered that there were a couple of small patches of BGA in the tank. The GBRs and Garras did not survive.

I therefore wondered if the Garras and GBRs may have taken a nibble of the BGA, which was on top of the filter outlet nozzle. This seemed a possibility for the Garras but not the GBRs but I was lost for any other explanation. I knew that some species of BGA were toxic to a whole range of creatures.

I set up a new tank using water from the tank in which I'd had the GBRs and Garras. It wasn't long before BGA started to grow. So, I removed a sample of this BGA and took a look at it under my second-hand school microscope. The objective was to see if I could identify the species of BGA that was growing. A quick detour here is now called for:

Blue-Green Algae (BGA) is not algae at all but is a species of Cyanobacteria. I had my suspicions of what species I had growing in my tank from what I'd read. My suspicion was that it was something called Oscillatoria. Its identifying feature is that the tips of the filaments of this Cyanobacteria oscillate from side to side. And, guess what I saw through the eyepiece of the microscope? Yes! - filaments waving from side to side.

To be continued...

JPC

I’ve never heard of or had (to my knowledge) BGA. It was an intriguing read especially as you had to look down a microscope to confirm what it was...

Hi @LeakysLab

BGA is, unfortunately, not rare. I know a lot of people who have been plagued by this menace. It's notoriously difficult to eradicate when it appears in a tank. It can be 'imported' on plants, fish and other critters. Although it can be very visible once established, one tiny piece of filament is all it takes to get started. The reason I needed to view it under a microscope was to fathom out exactly what species of BGA I had in my tank. That's necessary to decide how to deal with it.

JPC

Sorry to hear about your experiences and fish loss @jaypeecee
I have panda garras in my river tank, and am very fond of their boisterous nature.

I have had BGA in at least one tank in the past. I can't remember which tank as it was quite a long time ago, but I don't remember having any problems with the fish. This BGA is the stuff that sort of peels off like a sheet when it on the glass, isn't it? I've definitely had that. I think I increased cleaning at the time, but it's likely that it was eventually eradicated completely when the tank was stripped down and re-worked - something I used to do a lot as I upgraded to larger tanks.