HELP! Fuzzy Stuff growing in tank!

What is this? On my granite stone and plastic plant. Fuzzy and most looks blackish. One looks reddish.

Black hair algea? I have some of that annoying stuff in my tank.

Did you remove it?

I’m about to! How did I get it?

That is black brush or black beard algae. It has more than one form. It is technically a red algae, but this is the first time I have actually seen it "red" (your first photo), and if memory serves me, the red form does occur in marine tanks. Most of the time, at least in my tanks, it is very dark green, grey/green or grey, or very dark brownish almost black. It is the only "problem" algae I have had to deal with in 20+ years.

It will grow on any surface, including rock, wood, filter stems, heaters, the tank glass in corners especially, and unfortunately plant leaves. I never try to eradicate it but keep it in check, which is not that difficult. Like all algae, it requires light and nutrients. I see it in some tanks but not others; it is interesting that a specific species of algae can appear in one tank but not others, while another species can appear in others but not this one. But balancing light and nutrients (in planted tanks) is the only way to deal with it. Anything strong enough to kill this will certainly harm plants, and fish.

I can explain further if asked. Photos below are the two most common forms, and I have had both at various times in various tanks.

Thanks so much, Byron! I was wondering why I only had it in 1 out of 5 tanks. Very odd. I read that Seachem Excel will eradicate it. Have you tried this? I have a bottle but haven’t used any in quite some time. The top pic that you attached looks exactly like what I have.

Deanasue said:

Thanks so much, Byron! I was wondering why I only had it in 1 out of 5 tanks. Very odd. I read that Seachem Excel will eradicate it. Have you tried this? I have a bottle but haven’t used any in quite some time. The top pic that you attached looks exactly like what I have.

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Excel is glutaraldehyde and water; this chemical is a very strong disinfectant used in hospitals, embalming fluid, anti-freeze, ship ballasts--to kill bacteria. It will when dosed according to the directions kill some plants. And it usually kills this algae, though Seachem do not endorse this. There is no way I would ever add something like this to a fish tank. It is not safe, regardless of what Seachem or anyone else says; "safe" does not mean just because all the fish don't die.

Balancing light and nutrients is the only effective control. I have had this algae appear/increase due to light duration in summer when the longer daylight even with blinds on the windows was adding enough extra light; due to over-fertilizing with Flourish Comprehensive; adding iron; when the tank lighting lessened due to the age of the tubes and I had not replaced them promptly; with too bright lighting for the plants; with lighting of the wrong spectrum.

I let it alone on wood and rock as it looks natural, and it provides a home for microscopic food critters the fish eat. It frequently dies off when the light/nutrient balance is restored and remains a greyish fluff.

Thanks, Byron. I had stopped using Excel because I never felt safe with it. I’ll start cutting my light time down. It really is a pretty algae but I don’t want it everywhere. I’ve been feeding baby brine shrimp to the fish since I’ve been hatching them for the fry tank anyway. Do you think they have encouraged the black algae? It’s the only thing I’ve been doing differently to the tank.

baby brineshrimp have nothing to do with black beard algae. The algae comes in as spores on plants, ornaments or in water and is a pain in the butt to get rid of.

Excel is effective at killing BBA, but Byron is correct - anything used to sterilize heat sensitive medical, surgical, dental equipment just doesn't belong in an aquarium. I would remove the plastic plant and rock and use hydrogen peroxide or a bleach/water solution to kill it...then rinse well. As for the tank, Byron gave some good advice.

Colin_T said:

baby brineshrimp have nothing to do with black beard algae. The algae comes in as spores on plants, ornaments or in water and is a pain in the butt to get rid of.

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Thanks, Colin. I just thought the shrimp may be more food than I feed with pellets and thought overfeeding may be contributing. Appreciate your input.

AbbeysDad said:

Excel is effective at killing BBA, but Byron is correct - anything used to sterilize heat sensitive medical, surgical, dental equipment just doesn't belong in an aquarium. I would remove the plastic plant and rock and use hydrogen peroxide or a bleach/water solution to kill it...then rinse well. As for the tank, Byron gave some good advice.

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Thanks, AbbeysDad. I did bleach the plants and rock last night. I have begun cutting back on lighting also. I think I’ll cut out the shrimp in that tank too so I can control the feedings a little better (with pellets). Got it all out for now. We’ll see how it goes.

baby brineshrimp swim around the tank for several hours and are more likely to be eaten than flake or powder foods.

Colin_T said:

baby brineshrimp swim around the tank for several hours and are more likely to be eaten than flake or powder foods.

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Thanks!

Hello
I too have this algae. I didn’t think it was bad. My tank is only about 3 months old. I have live plants with it. How do I get rid of it on live plants? I have a split 20 gallon with a Betta on each side. Difficult to clean. Will mystery snails help?
I leave my light on about 8 hours a day I have frogbit floating on top. With no algae.

Thanks so much!

Beatrice Welles said:

Hello
I too have this algae. I didn’t think it was bad. My tank is only about 3 months old. I have live plants with it. How do I get rid of it on live plants? I have a split 20 gallon with a Betta on each side. Difficult to clean. Will mystery snails help?
I leave my light on about 8 hours a day I have frogbit floating on top. With no algae.

Thanks so much!

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This algae is basically impossible to remove from plant leaves as it is firmly attached. The only way to deal with it is to solve the imbalance of light/nutrients so it doesn't increase.

Eight hours is not excessive but if the light is intense to begin with reducing the duration further might help. Can you provide data on the light?

If this is a 20g divided with just two Betta, other aspects to consider are feeding (minimal, not overfeeding), weekly partial water change of 50-60% of the tank volume, vacuuming into the substrate (removing organics is removing algae food). Plant fertilizers can add to algae if these are additives. If the frogbit is healthy, that is good as this plant and other floating species use a lot of nutrients as well as reducing light to the lower areas.