Question: Cyanobacteria

[kevintaco]

I have a 20 gallon tank (with 1 axolotl) with a "hang on back" filter set pretty low. I now have a serious cyanobacteria problem in the tank I think it could be partially due to the low filtration rate. I am getting a floating turtle island to disperse the water from the filter so that I can turn it up, but besides physically removing the "algae", is there anything I can do? I don't want to use erythromycin because the tank has only been set up for about 6 months. I also plan on changing the lighting in the tank, I think it could be too bright.

Thanks for any advice, it is much needed!

-Amanda

 

[auntiejude]

Algae and bacterial blooms are fairly routine in any tank. Light will be contributing to the problem too - along with high nitrates.

Try turning up the flow on your filter and adding a dense felt layer to filter out the tiny particles.

 

[kcoscia]

Cyanobacteria is normally caused by LOW nitrates in planted tanks. Lack of flow to the affected area is also very likely to be the cause.
Is your tank planted? Are you dosing any fertilizers for the plants? In planted tanks with fertilizers, what usually happens is, the plants can't take up other nutrients in the water column and grow due to the limiting nutrient of nitrogen through low nitrates. The abundance of other nutrients in the water column are what allow algae to grow, and specifically in this case, cyanobacteria because it can live in low nitrate environments better than other algaes.

Determine the cause and correct it or the algae will come back.
If the lighting is too high, raise the light, reduce the time it's on or get a lower intensity light.
Check your water parameters, especially nitrates in this case. If they are low but you don't have live plants or dose fertilizer, it's more than likely the light and lack of flow.

Once you take care or the cause then treat with erythromycin. For the course of the treatment, your biological filter should survive. Monitor parameters after the treatment to pick up on any damages (mini cycle) and do water changes until the bacteria catches back up. (I've done the erythromycin treatment on cyanobacteria and my biological filter survived 100%.)

If the erythromycin doesn't kill it, it isn't cyanobacteria.

Remember, with antibiotics, you need to complete the full course of treatment so you don't create resistant bacteria.

 

[kevintaco]

The tank has just a couple of plants, but I am trying to grow a moss wall on the back of the tank. I had a bunch of Christmas and Java moss that was dying (I waited too long to put it in the tank), which I removed. So there is just a little java moss in there from another fish tank I have. I do not use fertilizers.

The lighting is a florescent 20 watt tube. I don't know else about it because I bought the tank and hood used and it's kind of old.

 

[kevintaco]

I also have driftwood in the tank, could that be contributing at all?

 

[Elise]

Cyanobacteria is normally caused by LOW nitrates in planted tanks.

I don't believe this is correct as it is my understanding that cyanobacteria blooms are a frequent consequence of eutrophication.

...besides physically removing the "algae", is there anything I can do? I don't want to use erythromycin because the tank has only been set up for about 6 months.

You could try adding more plants, specifically duckweed which thrives in similar conditions to cyanobacteria. The duckweed will out-compete for nutrients through its exponential growth.

I would be reluctant to medicate the tank. However, if you do choose to proceed, you should consider if it would benefit your axolotl to keep him in quarantine during the process.

 

[allied123]

I had this exact same problem and what I thought was weird was that it was ONLY on the filter...a disgusting amount and I tried thoroughly cleaning it several times only for it to come back a few days or a week later (and in all honesty I might not have gotten it all off, too many small spaces!) Is it weird that it wasn't anywhere in the tank except on the filter?

 

[kjnorman]

Duckweed might do the trick. I had a couple fish tanks with duckweed for a while and it really cut down on algal growth - but be aware that it will also block light to other plants you may be trying to grow.

 

[kcoscia]

Duckweed or better yet, amazon frogbit! Easier to clean and remove and loves low flow environments.

I agree with the quarantine for your axie. The thing is, medication is the best kill all for this type or algae.

I think before we continue, we need pictures of the algae to be sure it's cyano.

 

[kcoscia]

I don't believe this is correct as it is my understanding that cyanobacteria blooms are a frequent consequence of eutrophication.




You could try adding more plants, specifically duckweed which thrives in similar conditions to cyanobacteria. The duckweed will out-compete for nutrients through its exponential growth.

I would be reluctant to medicate the tank. However, if you do choose to proceed, you should consider if it would benefit your axolotl to keep him in quarantine during the process.

I've never heard of that term until now, I didn't know there was a name for it!

Algaes are caused by that process, but cyano is one that can live in a low nitrate environment while other nutrients are in excess. I'm not sure if it's growth is limited to low nitrate environments, but I know that it is a trait of this algae to consider. My knowledge base is of planted tank origin, so in fertilized tanks, what usually happens is people are dosing nutrients but see this algae outbreak. Plants can't continue to absorb nutrients if a single nutrient is limiting. Nitrate or nitrogen is a highly important macro nutrient, so limiting leads to a stoppage of growth which leads to eutrophication of other nutrients. People are continuing to dose nutrients abd the excess grows and grows while cyano gets ready to feast. Since cyano doesn't require nitrates in high amounts to thrive, it gets comfy and decides your tank is the perfect home

 

[kevintaco]

I am pretty sure it is cyanobacteria. It has the right blue-green color (I know it varies), comes off in slimy sheets, and what I thought was the driftwood breaking down before is now obviously the beginning of the biofilm forming - that's what makes it come off in sheets. My tank doesn't smell, however. Attached is a picture.

Since my last post - I placed a sponge at the outflow of the filter and turned it up. It appeared to not cause too much of a current, but now my axolotls gills are really far forward. I also blocked the light in half of the tank in case that was contributing to the cyanobacteria.

I really don't want to use medication, will removing it be enough?

Today I got the turtle island pad thing, when I install it, can I turn the filter output all the way up? I'm really worried about him, I don't know why he is so stressed.

Thanks.

 

[kevintaco]

I'm sorry - I realized I left out that I did use plant supplements before in the tank but stopped a few months ago after reading that they were bad for axolotls.