So i did a water change yesterday and i woke up today to find both of my ghost shrimp dead, i let the water sit for 24 hours, and conditioned it with nutrafin aqua plus (which they haven't had problems with in the past), none of my other fish seem to be bothered though, i'm just curious as to what went wrong so i can try to make sure it doesn't happen again.

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30 gallon, self build
-1 male 3 female fancy guppies
-6 neon tetras
-3 oto
-1 male betta
-3 julie cory cats

Did you by chance use any copper-containing medicines or plant fertilizers? Shrimp have a problem with copper & it kills them apparently. They turn white/milky in color, then die. I've never had a shrimp come back after turning a cloudy, milky white....

Well I hate to say this.... But Ghost shrimp don't have the best reputation for living very long.
They are usually sold very cheap and in bulk as feeders, and are breed in bulk.
So you probably didn't really do anything really wrong.
Every now and then I'll buy a bunch of them and put them in one of my tanks, for cleaning, they died off and get eaten.
Out of 10 to 15 you may get a couple that last several months.
How long did you have them?

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"Buddha in your tank"

Another thing to note and not just with Ghosties, most shrimp don't tolerate big water changes or rapid water changes very good even if the water parms are perfect.

They are called ghost shimp, cause they have no life span.

Lol....
Or maybe cause there ghostly seethru?

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"Buddha in your tank"

I've had similar problems with ghost shrimp in the past. I find that they rarely tolerate major changes in their environment very well. I've loved all the ghost shrimp I've ever had, but in the future, I'm probably going to seek out slightly hardier varieties. Best of luck!

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"The Communitarium"
10 gallon freshwater tank.
Aqueon QuietFlow 50 cartridge filter.
Apple snails (Pomacea diffusa).
Ghost shrimp.
European weather loaches.
Malaysian trumpet snails.
Physella acuta bladder snails.
Brown Ramshorn Snails.
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"The Cochlarium"
10 gallon freshwater tank.
Marina S15 cartridge filter.
Apple snails (Pomacea diffusa)
Malaysian trumpet snails (Melanoides tuberculata).
Physella acuta bladder snails.
Brown Ramshorn snails.

As far as ghost shrimp simply "not living long" I disagree with that as being an acceptable excuse for shrimp deaths. Aside from what I've mentioned early I believe James has the best reason for the possible deaths.

Not only "major" water changes, but the SLIGHTEST changes to a shrimps water properties is a big deal to them. They can live in a tank without a water change for literally MONTHS, but once u do a small change it makes up a huge factor with their water parameter changing contributing to their stress. Shrimps are small crustaceans & as far as their contribution to an aquarium bioload, its minute.

I'm working under the information provided by the original post, and that indicates that there have been previous WC's with no problems.
(we have a tank with 2 ghosties that have been in there almost 3 months, and believe me I do lots of water changes)
I and I'm sure others are not saying that with inverts or any other tank occupant the need to be diligent in knowing that factors like WC's or other chemicals are important and can cause harm if not understood or done right. But I am saying that with a species like ghost shrimp they are know to be short lived, generally speaking.
And if they have been surviving WC's for months, I would applaud your aquarium care, and it is probably nothing you've done.

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"Buddha in your tank"

The estimated lifespan of 1 to 1 1/2 years is not what your going to see in a shrimp that has been breed in bulk, shipped to a LFS, held in stock tank, and then resold.
But as I mentioned... Statistically you may get a few sturdy ones that survive. Or if you get enough and have the right parameters, and a few get berried, hatch and grow... then those may live longer than expected.
I can think of only a couple of times that I've ever heard of glass/ghost shrimp living more than 5/6 months in an aquarium.

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"Buddha in your tank"