# Fish Paralysis after water change?



## arc (Mar 11, 2010)

So I did a big water -40%- change today before the holidays and the water was really cold. Right after I topped it up I noticed about 4-5 or more glowlight tetras that looked dead and just sink to the bottom or on leaves. They had colour, fins were extended and body was straight except they didn't move. When I fished one out I saw no breathing at all. Great start for the holidays! 

Turned on the heater and left them in there as I had a lot of snails, cherry shrimp and Cories that would eat them (They are small tetras so wasn't worried about spoiling the water).

About an 45 minutes later.....all the bodies were gone. Only thing I can see happening is either they came back to life or got eaten. The latter is hard to believe because of the timing(no big fishes) and the other creatures were not swarming any spot. 3 bodies were pressed up on the glass so its not like they drifted away.

So Paralysis is the other option....

Anyone else have this experience?


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## Cory (May 2, 2008)

Could be an overdose of dechlorinator. Certain fish are more sensitive to the stuff and will respond negatively to too much of it. What do you use to treat your water?


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## qwerty (Dec 15, 2009)

It's usually hard to overdose on dechlorinator... If memory serves Prime says you can dose up to 5 times the recommended dose just as a way of reducing ammonia toxicity should you ever have ammonia in your water for whatever reason... And I'm sure that's even a little on the conservative side just to cover their own liabilities.

You said the water was really cold... So the first thing that comes to mind would be "don't dump really cold water on tropical fish".

Fish are cold-blooded remember. Very drastic and sudden temperature swings can be very bad for them.

I don't recognize the symptoms personally from experience or anything, and I'm not saying that I try to match my water change temperatures perfectly. In fact I don't even check the temperature beyond a quick hand dip. But if it feels really cold to you, it's probably too cold for your fish.


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## waj8 (Jun 30, 2010)

I don't go ahead with the water change unless the change water temp. feels the same as the tank water temperature. I just dip my hand in the tank and compare that to the change water. I think it's a pretty accurate way to tell.


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## arc (Mar 11, 2010)

I used Prime at normal dosage 1 ml/10g. 

Always used only cold water because of fears of the hot water tank even though it's been replaced a few years back. However I normally only do a 20-25% and everyone in there was fine with it until now. I think the Cories even liked the cooler waters since they were always more acting after water changes. I'll start matching temperatures or aging water now since I don't want this happening again.


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## BillD (Jun 5, 2006)

I almost killed a tank of fish when i walked away during a top up with straight cold water. It ran long enought to drop the tank temperature so that none of the fish showed any signs of life (2 angels, 5 corys, and 2 BNs). I quickly drained about a third of the water and added very warm water to bring the temp up quickly. All the fish survived. I'm reasonably sure that if I had done it more slowly they would have perished. I suspect you had a similar episode. Do not be afraid to use hot water from the heater.


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## qwerty (Dec 15, 2009)

There's really nothing wrong with the water in your water heater. I would tell you if I've ever heard any reasonable arguments otherwise. People have been using tap water in systems far more delicate and sensitive to impurities than what most of us are running, without any problems short or long term.

If you're worried about anything like lead in your water, run your taps for 5 minutes to bring fresh water into your pipes.

If it's cloudy water that makes you uncomfortable, I assure you it's just oxygen and will clear up on its own if you're patient.

Keep things simple


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## arc (Mar 11, 2010)

Everyone in the tank looks fine now...I think I did lose a few tetras though. 

Thanks Bill for the info, looks exactly like what happened to me.

I'll start using warm water out of the taps now as I don't want this happening again.


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## theeyrietrainer (Dec 9, 2010)

That sounds like temperature shock. It can be fatal for fish but its just from the sudden temperature drop from you using very cold water and changing so much of it. If the fish is strong enough, it can come back from it but the weaker ones will die off from it. Next time, just use water at similar temperatures or at least room temperature, or if you still use cold water you should change far less. I wouldn't advise using cold water to change the tanks anyway, it stresses fish out too much.


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