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RCS deaths, unknown cause.


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Well my shrimp are suffering an apocalypse and I quite honestly can't figure out what's going on. Hence why im on a shrimp forum. I've already read about each disease known to shrimp. I've already read about what conditions they need and what toxins can harm them. Still can't pinpoint what the cause is.

So let's start with my halfway decent water perimeters and anything in my tank. Yes it's a planted tank with cholla wood for the shrimp and a ceramic decor. It is also heavily planted.

Inhabitants Had 60+ RCS but less than 10 now, 1 female Clown pleco, 1 male honey DG. The honey dg is innocent and leaves the shrimp alone, the Clown pleco doesn't mind the shrimp, she might crush some but I would expect the shrimp that habe been crushed to appear crushed, they do not.

Co2 injected 20-30ppm 8 hours a day. PH is 7.4 without co2Co2shuts off 1.5 hours before the light turns off.

Phosphate 0.5-1.0ppm (dosed)

Potassium 5-20ppm (dosed)

No ammonia, ammonium or nitrite.

Nitrate 5-30ppm (sometimes dosed, I try to keep it under 20ppm)

Seachem Micro's is dosed twice a week. 

Temp 75°

TDS 340

25% water changes a week. I use RODI water dosed to 5kh and 5dh with seachem buffers and seachem equilibrium.


Seachem phosphate is dosed at a daily low amount to keep it floating around .5 to 1pmm. No other products are added to the tank. I use Seachem flourite substrate, the clay based one.

Alright now to the topic of their deaths and history. A few months ago I bought like 10 rcs, a few died but a few had offspring which bumped my numbers up to at least 60, probably had 1 death a week from molting issues from what i could see. After that that many more started dying, including many berriedshrimp. I need to mention I recently successfully treated scutariella on my shrimp with PraziPro, which didn't seem to affect death rates before, during or after. I've read scutariella are a harmless parasite. Filter has carbon normally besides for a few days after adding that PraziPro. Filter intake is covered.


I have been doing autopsies on dead shrimp. Some have black/rust spots on their shells only after death (or at least that i can see (photo attached of the worse dead shrimp in cup)) with no limb loss and their organs are essentially dark liquid after death. However some that die look completely normal inside and out, maybe I'm catching some dead ones a few days after, not sure. I noticed some of the shrimp have a yellowish hue to their front inside, but not entirely (maybe normal???), I posted 2 photos of the same shrimp with that yellow hue in the front inside below, others have it too, might be food in them, even saw some online with it that didn't have issues. I am wondering if it is the dreaded Micrococci infection dooming my tank.

Here is my own guess list of possible causes in order of most likely to least likely in my opinion.

1. Nitrate poisoning.

2. Micrococci.

3. Co2 related.

4. Other livestock guiltly of mass murder when I'm not looking.

5. Black/Rust spot disease (still not seeing any live shrimp with it which would make it lean to a symptom of Micrococci.

6. Seachem micro's are building up to toxic levels.

7. Seachem Flourite is leaching and killing them.

8. They are eating root tablets or its leaching into the water in a way I can't trace with tests.


I estimate all my shrimp will be dead within a week if this is not quickly solved. Thoughts? Hopefully someone on this forum can save them.




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Too many variables to pin something down, but if I had to guess I'd suspect pH swings or a lack of minerals.  The Nitrate levels are also unhealthy for shrimp, I would try to keep those below 10.  Ideally, they will be below 5.  


I'd start by testing pH at different times during the day to see that the levels don't very too much.  Also, grab a feeding dish and drop a mint flavored tums into it.  See if the shrimp flock to it and consume it.  If they do, then you may have a calcium deficiency.  


How much copper is in your ferts?  Maybe try backing off on those, copper is pretty toxic in some concentrations to shrimp.  


Hopefully some of this helps!

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When I neglected one of my cherry shrimp tanks, I had big females turn a DARK red, just like the color you have of the dead one.

I loved the color, but it was happening because they were getting killed from high nitrates! My nitrates were at an unacceptable level of 30-50ppm!!!

Just my input from some experience. 

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8 hours ago, ILikeAsianBooty said:

Take out co2/dosing. Feed more calcium. Try lowering TDS

I'm feeding calcium rich food, I made sure I did from the start. Co2 can't be stopped completely or hair algae will hit the tank so hard that I'd have to replace plants. I have it turned down to about 15ppm. I'll try to get TDS to under 300. My pH without co2 has been drifting upword's from 7.4 to 7.8 over the last month, definitely not good but I don't want to kick it down too fast or I'll kill them 😕

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Alright I have lowered tds to 290 with activated carbon. Green hair algae started becoming crazy so co2 had to be added back in at normal rates. Co2 is now a .8 point ph drop at 4dkh. Dropper test shows about 30ppm. Doing a water change right now that will drop resting pH by .2 over a few hours which should lower it to 7.6 once the Co2 fades off. so with Co2 my pH should be hitting 6.8ish. Nitrates are less than 5ppm now. Odd thing is when seachem alk and acid buffers are mixed together the acid buffer turns some kh into co2 which temporary drops the pH to near the tanks pH during co2 injection. I contacted seachem about it and they said once ro water is mixed up it should be added to the tank within an hour to avoid the kh from being eaten away from the acid buffer entirely. So far that logic is confirmed by my tests to be true.

Less shrimp fatalities lately, hopefully that goes down to zero so they can at least breed and kick start my population again.

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  • 3 weeks later...

Just an update, the deaths have stopped completely. I have about 5 to 7 shrimp left, all eating rapidly, active and molting a lot. A few are females. Hopefully they kickstart the population again.

I only made a few changes, so I'm not sure which one to give credit. I kept nitrates under 20ppm. I removed my sealed steel nail weight's from the tank and a bronze wire from inside my co2 tubing. And lastly I started a higher quality shrimp food for them.

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