# What is this red algae?



## Nathan Triplett (Dec 9, 2015)

I've had this red algae in my tank for the last year or so. I can't seem to shake it no matter what I try. I am actually not even sure what type of algae it is.

*Algae Description*
It's a dark red-brown with almost a purple hint to it. It's stringy and matted kind of like BGA. It does have a bit of an earthy, old dirt in the forest smell. It grows mostly on the driftwood but also grows on the rocks and plants as well.

It comes off fairly easily if you rub your fingers over plant leaves. A toothbrush on the driftwood scrubs it off very easily as well. It squishes up into a paste, but not a super slimy one, if that helps.

Neither Ottos nor Bristlenose seem to care for it at all. 









(full size image here: https://i.imgur.com/n9LHkuu.jpg

*Tank Setup*
The tank has been going for about 2 years now. 

Generally it's a tank for about 15 Zebra Loaches, but we keep a two schools of smaller flashy fish (minnows and neon green raspora) to fill up the top half of the tank. I used to have a school of ottos but there is only one left (we do plan to get him some more friends shortly). I've also had a brislenose at one point, but the loaches kept kicking him out of all of the good caves and chasing him around.

Tank: 75G

Light: 48 inch Satellite Planted + the light is fully on for 8 hours a day. There are another 4 hours when I dim to just darker and colored lights in the morning and evening.

Substrate: 50/50 smallish gravel and Flourite Black. 

Filter: 306 Fluval canister filter + Ehime canister Filter

Plants: 3 amazon swords, many small crypt lutea, a handful of tiger val, and a bit of wisteria. It's not super densely planted, but it's not completely sparse.

CO2: I added C02 injection about a month ago, timed with the lights. Takes about 3 bubble/sec to keep the drop checker green during the day.

*Ferts and Levels*

I put root tabs in around the plants every 4-6 months (I know I should do it more often, but I forget sometimes). 

I dose seachem N, P, K, Fe, Flourish, and Excel regularly. 5ml each of N,P,K twice a week, once a week for Fe and Flourish, and daily for the Excel.

There hasn't been Ammonia or Nitrites in my tank in 1.5 years. I try and keep the Nitrates between 10-20. Phosephates at between 1 and 1.5.

PH is just between 6.5 and 7.0 depending on the C02 levels. 

Our water is very soft (2.0 KH and GH) so I add in baking soda and epson salt with each water change to target around 4.0 roughly.

*What hasn't worked*
I've tried blacking out the tank. 
Adding more plants. 
Lowering the photo period down to about 6 hours. 
I've dosed EM once in case it's BGA related.
The CO2 I'm still hopeful will help in the coming months, but I haven't noticed it growing that much slower.

The algae appeared about 1 year into the tank's life. If I ignore it, it really takes over the driftwood entirely. I can pull the wood and rocks out, scrub them off, and it buys me about a month of nice clean hardscape. The slower growing plants also get covered over time.

*Help!*
Has anyone seen this beast before? It doesn't really match any pictures, and I'm running out of things to try to fix it. Thanks in advance.


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## Wantsome99 (Nov 27, 2016)

I'm not an expert on algae but from my experience over the past 25 years red algae is a sign something rusting in the tank. Either iron in the substrate or rocks. I had one of my heater break and didn't know it and had an outbreak of red algae from the coils in the heater rusting. If it's none of the above maybe it's iron in your water source?


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## Darkblade48 (Jan 4, 2008)

It reminds me of (unhealthy) black brush algae (BBA) that is dying.


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## Nathan Triplett (Dec 9, 2015)

The iron idea is interesting. I have been dosing Iron for the Amazon swords for a long time. I wonder if that could be part of the issue here. For the $10 it'll cost I may pick up an Iron test kit next time I'm in the store.

I've had a few small tufts of BBA in the past, but they never grew to larger than the size of a penny and were pretty distinct from the red stuff. Maybe it's some other strain though.

I appreciate all of the input!


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## Calebrh (Jun 17, 2017)

Darkblade48 said:


> It reminds me of (unhealthy) black brush algae (BBA) that is dying.


I agree with you here.

I just had some BBA groaning on one of my filter intakes. Then after some water and light changes, it started to turn red, then a retro pink color (which looked awesome) and finally a week later completely vanished. 

Give it some time. If it's not spreading, leave it alone and see if it just fades away.


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## Highseq (Jul 26, 2017)

Yeah thats what BBA looks like after I hit it with some hydrogen peroxide.


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## Nathan Triplett (Dec 9, 2015)

To follow up. I checked the iron levels and they are very low. The swords in my tank seem to eat iron just about as fast as i dose it. If anything the iron levels are probably lower than they should be (maybe the red algae is eating a bunch of it).

The hint that it reminds you of BBA made me start searching for 'Red BBA' and I realized there are dozens of types of different BBA which all seem to behave differently. Some pictures of Audouinella seem pretty close to what I have. 

Since I am running CO2, and my levels seem to be in normal range, and I was looking for a few new fish I took a shot at adding 4 molly's to the tank. Turns out they really really REALLY love eating the stuff. Eating it is about all they want to do all day and all night long. After 3 days they've managed to remove about half of it. I'm really hopeful that once they'll finish it off and then nibble out any bits of it which re-appear.

Thanks for the replies and help. I'd not have tried buying the Mollys if you hadn't helped me decide that this really was BBA after all. 

Cheers and happy fish!


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## Moonjelly (Sep 17, 2017)

you have a RED form of BGA. Mollies eat the stuff. clean as much as you can and then introduce 2 black mollies. minimize feeding and let the go to town. how are your phosphate levels?


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