Horrible Black Stuff In Tank. Algae?

[greengoddess]

Hi everyone,

My tank has been up and running nicely for a few months now. It has the usual green algae growth that needs cleaned occasionally but over the last few weeks I have noticed a horrible black coating growing on all the artificial plants and just recently it has started to grow on the glass. At first I assumed it was normal algae but when I came to scrape the glass yesterday all the black stuff came off in sheets like black skin (unlike green algae which seems to scrub off into a mist). The stuff was in hundreds of bits floating around my tank. I netted a lot of it out and then did a partial water change.

Any idea what this stuff is, what causes it and how to get rid of it? The only two natural things (apart from my fish) I have in my tank is a large piece of driftwood (which was prepared properly) and a small Java fern. The black stuff is also all over the driftwood and Java fern. Could the driftwood be the culprit?

For the record I have two fancy goldfish and 12 mountain minnows in the tank (240 ltr).

 

[AstonN24vantage]

tank size
parameters.
picture?

 

[greengoddess]

tank size
parameters.
picture?

Hi

The tank is 240 litres, standard rectangular tank (Jewel Rio 240). I have got rid of all the black stuff off the glass and also what remained floating in the tank. I could take a photo of the black stuff on the leaves of my artificial plants if you think that would help.

 

[waterdrop]

Are you sure its not brown algae (also known as diatoms) that you are describing? It looks like tiny dark brown spots at first on the leaves, whereas it looks like a brown mist in the glass (in corners typically) at first. If the over-lighting is very stong or there is sunlight hitting the tank then the diatoms can become a mat of algae.

On the other hand it could be some kind of black fungus. Its a good idea to remove and wipe down all plastic plants and decorations during the weekly water change unless they have extensive little leaves.

If its brown algae you may have your lights on too long. If you don't have live plants the light should only be on during main viewing.

~~waterdrop~~

 

[greengoddess]

Are you sure its not brown algae (also known as diatoms) that you are describing? It looks like tiny dark brown spots at first on the leaves, whereas it looks like a brown mist in the glass (in corners typically) at first. If the over-lighting is very stong or there is sunlight hitting the tank then the diatoms can become a mat of algae.

On the other hand it could be some kind of black fungus. Its a good idea to remove and wipe down all plastic plants and decorations during the weekly water change unless they have extensive little leaves.

If its brown algae you may have your lights on too long. If you don't have live plants the light should only be on during main viewing.

~~waterdrop~~

Hi Waterdrop

The lights in my tank are on a timer for 8 hours per day. The tank is not in direct sunlight. When I scraped the stuff off the glass it looked black rather than brown. It didn't come off in a misty powder like green algae does when you scrub it. It came off in a black film which broke up and floated around the tank. I've attached a few photos of the leaves of my artificial plants and also of the piece of driftwood. They are all covered in this stuff. I must admit that this last water change and vacuum was over 3 weeks since the previous one (due to holidays and laziness). If I get back to my routine of doing it once per week than hopefully I will be able to keep it in check. I just wondered what this stuff was and if it is harmful because it looks horrible.

.

 

[WILDER]

What filter are you using. You need double filteration with goldfish.
Does the black stuff smell bad.

http/naturalaquariums.com/plantedtank/0608.html

 

[greengoddess]

What filter are you using. You need double filteration with goldfish.
Does the black stuff smell bad.

http/naturalaquari...dtank/0608.html

I'm using the filter that came with the tank. Not sure what it's called but it's a very big filtration system with plenty of power and media content. Also, the two goldfish in my tank are still quite small and it is a 240 litre tank so the filter should handle their waste without a problem. I can't say I noticed any smell from the black stuff. It seemed to be relatively odourless.

 

[WILDER]

Even if the goldfish are still pretty small there still massive waste producers.
You need a filter that turn over 100 gallons.

Here another link.
http/www.aquariumpros.com/articles/algae.shtml

You need more filteration.
Gravel vac. Water changes.
Cut down on lighting and feeding.
Maybe invest in a uv lamp.

 

[greengoddess]

Even if the goldfish are still pretty small there still massive waste producers.
You need a filter that turn over 100 gallons.

Here another link.
http/www.aquariump...les/algae.shtml

You need more filteration.
Gravel vac. Water changes.
Cut down on lighting and feeding.
Maybe invest in a uv lamp.

My tank's filtration system turns over 1000l/ph (that's 264 US gallons per hour).
Usually I do a gravel vac and water change every week. I may have been overfeeding but I am not sure. I will try cutting down the food a little. Thanks for those two links, they have very useful info.

 

[Dave Spencer]

The two links provided seem to be giving different advice. The first link to BGA is, I would say personally, very good. The second one, blaming nitrates and phosphates is, in my opinion, utter drivel that has been holding the hobby back for a while.

One other thing to consider with BGA is that it often originates in substrate where flow is low, and it receives a lot of light ie. at the sides of the tank where day light may hit it. If this is the case, try taping up the area of exposed substrate so that it receives no light. Defeating it in a planted tank is a much easier proposition, by increasing/improving flow around the tank, and upping nutrient levels, nitrates in particular.

Black outs are effective,but try eradicating the causes first, otherwise it will return straight after a black out. I wouldn`t go down the medication route, and a UV will be nigh on useless on anything other than green water.

Dave.

 

[waterdrop]

Wilder and Dave, at the risk of seeming a little dense here, are you both saying that based on the pictures (or the text?) you are both pretty confident that the diagnosis is BGA/Cyanobacteria? (or are you just discussing BGA -in case- the diagnosis turns out to be BGA?)

WD

 

[Dave Spencer]

I know what you mean WD. The photos look like diatoms, but the OP`s description of a black film suggests BGA. Perhaps both types, plus others are present.

Dave.

 

[waterdrop]

Yes, I'm glad to hear you say that because I was thinking, with the pictures a little fuzzy, that it looked like it could perhaps be either. I've seen diatoms, when they haven't been touched in a while begin to mat up and look like that and then when you wipe them off they peel off into black debris floating around. On the other hand I know BGA is not always blue-green, right(?), it either goes through different stages or dies or (how?) looks brown(?), black(?) (bring us up to speed on that, I forget what I've read about that and I've never (knock on wood) experienced BGA myself.)

WD

 

[WILDER]

Sorry about the 2nd link I don't have that link in my favourites. Was more for the colours in algae than anything.
As black slime stuff can be bad bacteria than algae.
Blue or green algae can turn into black thick sheets.

Hope that makes sense.

 

[greengoddess]

Thanks everyone for all your help. As I have already cleaned up the worst of the stuff I am not really able to accurately identify it. After your advice I have reduced the daily lighting to 6 hours and will try to keep on top of the weekly water changes and gravel cleans. The next time I do a water change I will clean all the artificial plants. Other than that I will just have to keep an eye on the tank to see if it starts to become a real problem. If it does... I'll be back on here for more detailed advice, hopefully with better photographs of the culprit.