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Blue Green Algae?

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We bought a moss ball for our son’s tank awhile back. He did not take care of it/didn’t listen to us and it died. We had to empty the tank and clean everything to get rid of the dead moss (including scrubbing the gravel.)

A little bit after that, this black stuff started growing. We didn’t know what it was. So we just keep pumping it out. However, it keeps coming back quickly and our 2 fish aren’t doing so well. 

I took a sample of the substance and posted a picture here. (The substance is in a blue bowl, so that is not the color of our water.)

Is this blue green algae? There seems to be tufts of something blue green. Or could the moss be trying to grow back from the tiniest of particles? Any help would be appreciate so we can treat the tank and the fish (CoCo and Shady) that we are pretty attached too. 


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Could be. If so, it is cyano-bacteria. Not actually an algae. Does it stink like a swamp when you smell it? Kind of a smelly sulphur stench? If so, I'm sure that's it. Clean out all you can manually -- I use a fish-tank-dedicated turkey baster. Do a 50% water change. Lower the lighting. Feed less. If you are desperate, you can try to hit it hard with Maricyn (Fritz Aquatics formula of E. M. Erythromycin).

Here is a good blog article from ACO about getting rid of it.

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