# Blue green cyanobacteria in sulawesi shrimp tank (tips?)



## DesmondTheMoonBear (Dec 19, 2011)

Recently I’ve had some of this nasty stuff sprout up in my cardinal shrimp tank and am looking for the cause while I attempt treatment...emphasis on attempt.

The tank is a 20 gallon long lit by three 23 watt CFLs for 13 hours a day, and filtered via an Eheim 2211 and sunsun 304b. (with flow adjusted accordingly for the latter) There are lava rock piles for the shrimp, and the substrate is 1/4-1/2” of pool filter sand. 

So far the aquarium is 2 months old with approximately 150+ cardinal shrimp. No plants aside from green spot/dust algae and diatoms. The sand and the sunsun were in and running on a previous tank for 3 years, before being cleaning and introduced to this one, with the shrimp being added 2 weeks later. I add a small amount of Bacter ae for the shrimp once a week, and have been aiming for monthly water changes and weekly/bi-weekly topoffs with RO/DI water. 

As of now the BGA has setup shop on a few patches of sand and some lava rock in several different spots in the tank. It first appeared as a teeny spot 3 days ago and has grown fast, though I’m hoping I caught it early, as I’ve seen what it can do but have never dealt with it personally before. 

The water/water changes comes straight from my tap which is treated with prime, and the in-tank parameters are as follows:

Temperature: 82F
PH: 8.4
Ammonia: 0
Nitrites: 0
Nitrates: 0
GH: 10
KH: 7
TDS: 200

As for the cause...the light has been running a good bit in an attempt to grow good algae for the shrimp, since they feed on little else but just that and biofilm. I’m thinking chances are good it’s contributed. I’ve also read a fair bit that low nitrates can play a factor, though as far as I’m concerned 0 nitrates is ideal for a Sulawesi shrimp tank. I doubt the high temperature helps, but lowering that is out of the question. As for any other cause...I’m at a loss. I do have a test kit coming for phosphates, so an imbalance between phosphates/nitrates is not out of the question. I’ve yet to test phosphates out of the tap. 

For treatment, I (very carefully) conducted a 35% water change, added an aerator, and now have the tank on blackout for a planned 5 days. I slightly increased flow but can’t much more without severely bothering the cardinals which if anything prefer stagnant water. I will attempt another water change at the end of the blackout, along with a reduction in photoperiod to 8 hours. I can’t imagine I can do much more, and am worried if this treatment doesn’t work. With over 1k worth of extremely sensitive shrimp in the tank, I’m extremely reluctant to try any of the praised antibiotics/saltwater slime algae treatments...unless somebody else has dosed a tank with sulawesi shrimp and experienced minimal losses?

Would very much appreciate any input and suggestions. Thanks!


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## Asteroid (Jul 26, 2018)

In the past I've used EM Erythromycin API with RCS and Amanos without issue. Completely gets rid of BGA in a few days, but do your own due diligence for your shrimp.


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## DaveKS (Apr 2, 2019)

That’s a lot of shrimp and shrimp poop for 20gal. You should probably try running Purigen in one of the filters full time to get DOC down.


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## DesmondTheMoonBear (Dec 19, 2011)

I do have purigen dedicated for one tray in the sunsun actually; 250ml worth of the stuff. Checked the filter a month in and it still looked good. Definitely over-filtering with the sunsun but that was the goal. I’ll recheck after the blackout just in case it did for some reason exhaust already.



Asteroid said:


> In the past I've used EM Erythromycin API with RCS and Amanos without issue. Completely gets rid of BGA in a few days, but do your own due diligence for your shrimp.


It’s comforting but so far I’ve only seen reports with shrimp tanks housing hardy species. Cardinal shrimp will definitely be up there sensitivity wise along with high grade CRS and the like.


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## minorhero (Mar 28, 2019)

So a couple of things. How sure are you that its Cyano? If its actually Cyano then be aware that your blackout will not help. Its bacteria not algae. It doesn't need light to live. If its not Cyano but algae then your blackout should work wonders. 

Its confusing because its commonly called Blue Green Algae because thats what it looks like. But cyanobacteria is a bacteria.

Cyano stinks like a swamp. If you disturb the suspected cyano and then smell your tank does it stink? If so then you likely do have cyano.

As to how it got to your tank. Well it either came in via something in the air or with your shrimp most likely. Its bacteria so it can come into the tank like any other bacteria.

Erythromycin is an antibiotic. Its actually used to treat human patients in hospitals. I have never heard of it harming anything in tanks. Since you have so many shrimp and want to be sure you could set a couple aside in another container and mix in some Erythromycin to see if that hurts them.

And finally, if you want to do it without any chemicals whatsover. I would do 2 things. Remove anything that has the cyano on it (substrate, rocks etc) and then dramatically increase flow. Buy a cheapy HOB etc.


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## CarissaT (Jul 1, 2019)

Having too much light intensity will be a huge contributor to bga especially with high organics and low circulation. Take out a little piece and smell. If that’s what it is, it will completely stink! Blackouts will stop new growth but won’t kill what’s there, manual removal and lots of water changes along with reducing light intensity by a big chunk and increasing circulation is the only way to make a sizable dent. It’s pretty awful stuff. 


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## DesmondTheMoonBear (Dec 19, 2011)

There’s really no question about it’s ID, I’m used to seeing the stuff all over Florida’s lakes/retention pounds, especially the ones that get hit with loads of runoff. True algae can’t compare in its speed of growth either. 

I got some erythromycin just to have on hand in case I work up enough courage to use it. I was meaning to end the blackout per suggestions/supposed usefulness and perhaps try it, but with a quick peak it looks like the BGA is dying off? It’s all turned a light green and is lifting up off the rocks/sand. I’ll continue the blackout just to see if it continues. A quick google does show some other folks that have had luck with little more than a blackout.


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## Desert Pupfish (May 6, 2019)

I can vouch for the stink--"old hiking boots" is how a couple of longtime members here described it, and that was pretty accurate. I used erythromycin and it worked--but the most delicate inverts I had were ghost shrimp, who seemed unfazed.

A month later and it looks like it might be coming back (mine keeps manifesting as combination GWA/BGA) so after reading some threads here got a UV sterilizer (Green Killing Machine) . Hasn't been in 24 hrs yet and I'm already seeing an improvement. It sterilizes both algae spores & bacteria--people with delicate fish like young discus swear by it on here. You might try asking other shrimpkeepers on here if they've had experience with using these.

Good luck!


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## DesmondTheMoonBear (Dec 19, 2011)

Hm, the sunsun has a UV bulb in it, but that burnt out awhile ago. Perhaps time to order a replacement?


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