Dark green algae/mold?!

[s.moriarty]

I noticed this a while back, but it was very small for a long time, so I didn't think much of it. Today I caught a glimpse of it, and it looks like this!!

It's various shades of green, mostly nearly black, and growing on the under side of the glass beneath the light fixture.

My 29gal tank has been running and stocked with small handful of fish for a few months now. Water tests show all normal values for ammonia, pH, nitrates, and nitrites. There is recently a small algae bloom on the glass sides of the tank, but I'm not concerned about that at this time. Should be an easy fix.

But what is this nasty growth on the top glass??? That piece of the good I currently in my bathtub, sprayed down with bleach. I hope that was safe. I panicked.

 

[enrgizerbunny]

It's right over top of where your filter splashes? Or over an air stone?

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[Mama Karoti]

My guess is BGA. Does it have a strong "fishy" odor?

 

[Coryluv]

Wow, I can't tell from the pictures but it sure is impressive. What I can see kind of looks like cyano. Just make sure you thoroughly wash the bleach off when you are done. When I use bleach I also soak whatever it was in water with some Prime for insurance. Was it straight bleach or diluted? Just curious. Not much survives a bleaching. Dilute bleach is how I'd have handled it.

 

[s.moriarty]

It was right over the filter! The tank also gets a good deal of natural light, as it's in the living room, which has a sliding glass door, and the shades stay open most of the day for our potted plants, and the few live aquarium plants.

I didn't notice any fishy oder actually. Even before bleaching. If it was mild, I may have missed it in all the squirming and "Ew ew ewwww!!!"ing I was doing.

I used a spray bottle of Target (the store) bleach. I don't think it's diluted. I'd check, but it's still in the bathroom and my boyfriend is showering lol (I did hit the tub with mad Scrubbing Bubbles after the genocide of whatever that stuff was).

I rinsed the glass very thoroughly before putting it back, and it IS above the water, not actually touching it.

But the bleach seemed to do the trick. It all came off in pretty much one big slimy piece. Eeeeh.?

 

[Coryluv]

The fact that it came off in a sheet seems to support it's being cyano or BGA (two names for the same thing) even if it didn't smell that fishy. There are many many different strains of cyano and I'm sure some of it smells worse than others. In fact, spirulina is a strain of cyano. Saying something is cyano is as specific as saying something is a fern vs a tree. In this case saying it is cyano vs real algae. Since it is above the water I'm sure a really good rinse will suffice. Ewwww is right.

 

[NewToFish1989]

I used to get this alot on my cichlid tank, it was caused by my air stone splashing and hitting up against the hood. After I turned the pressure down and moved it away a little, no longer get it.

 

[enrgizerbunny]

What is cyano?

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[Mama Karoti]

Cyano is actually a bacteria. It is not algae, although it has the characteristics of algae. I get it on my glass top, too. I just wash it off and periodically bleach it. I did have an outbreak in my tank once and treated it with Maracyn (an antibiotic) to get it under control. I think it is always around, it's just a matter of whether it is an "outbreak" of it due to aquarium conditions.

 

[schoeplein]

Natural light is only going to exacerbate the issue. I'd do what I could to shade the tank from the sun. You also probably have a high level of nutrients in your tank. Is it planted? How often and how much water are you changing? How often are you feeding?

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