# Water change kills shrimp, doesn't harm CPD or fry



## bdement (Jun 4, 2007)

I have a 29 gallon tank with ~80 Cherry Shrimp, 10 CPDs + fry, where I do 50-60% water changes weekly. 24 hours after yesterday's routine water change, about 20 shrimp (that I could find) were belly up, and it looks like more are on the way. They are young and old, and similar sized shrimp are all still living in the tank. Snails and Celestial Pearl Danios, even fry, are all fine so far. 

My theories are limited, this is the first time I've had a tank set up for more than 1 year in a single location, so I'm looking for some insight!


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## Jane in Upton (Aug 10, 2005)

Ouch!

I assume you use a chlorine/chloramine treatment? If you change that volume of water (~15 gallons) quickly, when do you add the water conditioner? I'm wondering if it might be a chloramine "shock"? How about temperature of the water - perhaps the fish were more able to withstand a large temperature drop which was too much for the shrimp?

Also, do you have a test kit to see if anything is "off" with your local water supply? I recently had a mysterious instance when I had a sudden shrimp die-off, and in scanning the local CATV channel, found out they were doing "Seasonal Hydrant Flushing" that weekend - argh! For nearly a week afterwards, my water came out of the tap with a pH of 8.2+ (test kit only went up to there), and I never was able to get any dKH or dGH readings - it was so high as to be off the chart - I stopped at 20 drops added to the test vial without the indicator change. I repeated each test 3 times to be sure it wasn't a fluke. I called my local water guy, and asked about it. Around here, straight KOH is added to counteract the naturally acidic water (which has been wreaking havoc w/ local old water mains) and I asked him about the hardness, too. Surprisingly, a few days later, the water is coming out at 7.6 (still alkaline, but workable) and the dKH and dGH are in the 5-ish range. 

I'd strongly suggest getting hold of a test kit. Since its a crisis-in-progress, if you're not able to do that, then perhaps if any of your shrimp are still kicking, you might try a water change with some "spring water" from a local supermarket might save them. I finally did that with my problem tank. The local gallon bottled water was pH 6.4, and negligible carbonate and general hardness. I changed out 50% to bring the numbers down. Store brands are around 2/$1, which is probably worth it if you've got a lot invested in your shrimp.

Best of luck - this sort of calamity has happened to many of us!
-Jane


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## dgphelps (Jan 1, 2008)

What did you use for the water change? Tap water, RO water, bottled water? I wonder if your source had copper contaminant. That wouldn't harm the fish, though it should have killed the snails too.


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## ErioLover (Apr 30, 2009)

What a mystery. Was there a big temperture change?


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## tex627 (Nov 2, 2008)

did you mess with the filter?


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## bdement (Jun 4, 2007)

Thanks for all the replies and a few ideas that I hadn't considered. One new symptom that to me makes it clear that something changed in my tap water is that my crypts are now melting! Or could that be from all the death and bodies turning up in the tank?


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## Jane in Upton (Aug 10, 2005)

Aha... Crypt melting is most likely due to a change in your water!

I don't think the shrimp bodies would cause that much of an ammonia spike (I assume you didn't leave them in there to decompose). It would affect other shrimp, but not likely the crypts.... that points to something in the water, IMO. Especially since you say the tank is established, so I assume the crypts aren't new, or moved. Also, the crypt melt takes a little while to set in, which also affirms the "something's changed in the water" theory.

Have you been able to do any testing? You might even consider contacting your local water authority to inquire. 

Any more shrimp losses since that instance, and how are the fish - something toxic might take longer to build up in them and show. The old exposure/dosage criteria ... shrimp are exquisitely sensitive to this sort of thing.

-Jane


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