# wild cherries mass die off



## n0otro (Nov 22, 2006)

I started out with about 20 wild cherries ([I)Neocaridina denticulata sinensis[/I]) and up until yesterday had about 40 + tons of fry and females with eggs all over my 10 gallon tank. I was doing a regular 50% water change yesterday and before I even added the new RO water, about half of my shrimp were seemingly lifeless lying on their sides. I thought it might be due to lack of oxygen, but my neon tetras weren't gasping so I didn't think too much about it other than to hurry up and add the new water and get the tank circulating again. Well, a few hours after the change, the majority of the shrimp seemed to have come back to life, with only maybe 4-5 shrimp actually turning milky and dying.

Today I did another 50% water change because I was replanting some _Hemianthus callitrichoides_ and almost all of the shrimp are lying lifeless on their sides with a little bit of pleopod movement, probably a good ~20-25 are milky white and look like they are beyond rehabilitation. Most of the fry are also on their sides, however they are showing more movement than their adult parents.

I tried adding half a cap ~2.5ml of H2O2 to quickly spike the oxygen content of the water, but it doesn't seem to be doing anything. 
The tanks pH is 6.4 and my nitrates, nitrites and ammonia are all very low. kH is about 2.0 and my CO2 content is up around 25ppm

Not too big of a deal since I have a whole streamfull of wild cherries right behind my house, but I was curious if anyone might know what caused this massive die off as it doesn't seem like lack of dissolved oxygen is the problem

Thanks


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## BryceM (Nov 6, 2005)

Are you vacuuming the substrate during the WC's? I've had fish go belly-up after disturbing anaerobic pockets in the substrate. At least, that's what I suspected. Large gas pockets from deep in the substrate were released by the vacuuming and fish in the immediate vicinity kicked over almost instantly.

Just a guess.


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## milalic (Aug 26, 2005)

guaiac_boy said:


> Are you vacuuming the substrate during the WC's? I've had fish go belly-up after disturbing anaerobic pockets in the substrate. At least, that's what I suspected. Large gas pockets from deep in the substrate were released by the vacuuming and fish in the immediate vicinity kicked over almost instantly.
> 
> Just a guess.


Gotta agree with this. Also, another thing is that your water parameters changed, thus killing your shrimp.

-Pedro


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## fish newb (May 10, 2006)

Are you just putting RO water in there? It's probably not a good idea if so, it lacks electrolytes and other things and can kill stuff pretty quick... or so I've been told. That's why people usually mix it with tap water or add their own trace and stuff to it..

So maybe this could be it as well as screwing up your substrate?

-Andrew


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## n0otro (Nov 22, 2006)

The shrimp definately all went lifeless before I did any replanting(thus barely moving the substrate), which was minimal and the fish didn't show any signs of lack of oxygen. 

I've been using RO water for years with my planted tanks w/ shrimp and have never had the problem. I actually even used about a gallon of dechlorinated tap water because I ran out of RO.

But the shrimp went belly up BEFORE I even added any new water, they went belly up after I siphoned the old water out so I'm 100% positive it's not a new water issue. It's weird because it happened after I siphoned water out, but before I replanted stuff and before I added any new water.

I'm baffled


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## John P. (Nov 24, 2004)

Were there a bunch of them at the surface of the water? Something simalar happened to me in the past after rescapes. I think it could also relate to O2 deprivation.


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## Ankit (Dec 9, 2006)

50% water changes? Isn't that a bit large?

It would be much better to do 2x 25% water changes over two days or so because it will disrupt them less. Was there a change in water temperature?

In any case, 50% is too large of a change IMO.


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## Purrbox (Jun 1, 2006)

I do weekly 50% water changes on all of my tanks, including my RCS breeding tank, without any problems. Sometimes I even do as much as 75% waterchanges, still without any problems. As long as the water changes are performed regularly enough and the temps are matched so that there isn't a huge difference in the parameters of the old and new water, there shouldn't be any problems with large water changes. In fact I find that my shrimp are more active, out and about exploring and eating, right after a water change than the rest of the week.

I have to agree that it was problem either something being disturbed while the water was being removed or a lack of O2 as a result of the reduced O2. If you aren't injecting CO2, you could try increasing surface disturbance to increase gas exchange and O2 levels. If you continue to have problems with shrimp this would rule out O2 as the problem.


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## argblarg (Aug 10, 2006)

I see you added hydrogen peroxide directly into the tank at some point? See this old link, they discuss shrimp dieoff when adding H2O2. They used a higher amount but it is still something to consider. Their shrimp continued to die for a few days after the addition. Hydrogen Peroxide as Algae Treatment?


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## mrbelvedere138 (Jan 18, 2006)

It is very difficult to know why shrimp die. Especially when it isn't obvious. I've had 11 snowballs die on me all at once. I think it was due to new plants from Asia I had recieved. Maybe they had some copper based disinfectant on them.


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## n0otro (Nov 22, 2006)

John P: none were at the surface gasping, they were laying on their sides with their pleopeds moving

Ankit: I don't usually do 50% water changes, however I was replanting stuff so it was necessary. However I have done plenty of 50% water changes in my time and have never experienced any negative side effects

Argblarg: I have to rule out H2O2 as a problem since I added it in RESPONSE to the problem, not prior to it happening.

mrbelvedere138: I had been entertaining your idea of some foreign trace metals or unknown substance that was introduced into the tank possibly by my hands during the siphoning of water, but I can't figure out what it would have been, and why, if it wasn't specifically detrimental to invertebrates, it didn't harm my tetras also... I think you're on to something here though. now if i could only figure out what....


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## Wood (Jul 27, 2006)

definitely sounds like contamination during siphoning. How exactly do you siphon the water? where do you store the siphon tube?

Shrimp are more fragile than neons, that is for sure. neons are actually extremely hardy from my experience with them.


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