# Help! I think I killed all my friend's fish with a water change



## Sandy Landau (Jun 4, 2010)

Yesterday, I changed the water in a friend's tank to give her a hand. All the fish were fine before the water change. Today, there are 2 dead corydoras and all the other corydoras look like they are dying. Some have red spots all over them, one has a white blister.

What did I do? I used just fresh tap water and Prime. The temperature was an exact match for the tank, within 1 or 2 degrees. I put in a small amount of Replenish for gh, the same as she does, about 5 ml per 10 gallons. I changed about 40% of the water in the tank, but this tank gets 25% water changes every week so that's not a big change.

She doesn't know about this yet, either, and I feel sick to tell her. Honestly, I had the best intentions. Is there anything that I can do to save the other fish? I have never seen anything like this in my whole life!


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## Kitsune (Jul 17, 2010)

It could be that there was more chlorine in the water than usual, I suggest putting another dose of Prime in there to neutralize the chlorine (or chloramines). It'll also help heal the fish a bit.

I dont' think Replenish would cause this to happen.

Check the temp, make sure the heater is not broken.

If the fish are dying because of the chlorine, there is a risk that the beneficial bacteria may have died as well. If she has some Stability, put some in.


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## Sandy Landau (Jun 4, 2010)

Kitsune I have put some different dechlorinator in the tank, Tetra Aquasafe, just in case. I am afraid of Prime now because I used it last night. 

The poor fish look horrible, dying right in front of me. I have never seen anything like this! What a nightmare. I keep pulling out the dead ones so that the other ones don't see their bodies.


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## Kitsune (Jul 17, 2010)

How much Prime did you put it?
I'm not sure what else to suggest right now... If you are near any of the good LFS (like Island Pets or Aquariums west) they can test the water for you right there and then. But I'm not sure if they have anything to test beyond the normal things though (like testing for chlorine levels).

Does she have another fish tank? The only other thing I can suggest is to find someone who has an established fish tank to put your fish in. That way you know that the water they are in is clean. The risk is that you might shock the fish (and possibly kill the weak onse), but if there's anything wrong with the water they are in (chemically), this would be the best bet.

Where are you located (well your friend)?


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## Immus21 (Jun 14, 2010)

Is it possible you introduced a foreign chemical in while doing the water change? Soap on your hands, residue in a bucket etc. You may want to change the water again if this is a possibility. Just be forward with your friend she or he may have a idea to help save the fish...


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## neven (May 15, 2010)

I've seen it a few times where people wash their hands thoroughly before maintaining their tank for fear of introducing contaminents, not realising they are putting more at risk, especially with the antibacterial soaps.

If you need to wash your hands before fish tank work, use baking soda and rinse well.


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## darb (Apr 21, 2010)

kinda sounds like gas bubble disease to me.

If you filled directly from the tap that would be my first guess. It is more of a problem as the water temperature drops in the reservoirs.

In the winter I age my water 24 hours in a garbage can with a powerhead which allows the dissolved gasses and chlorine to escape and the water to come up to room temperature. Then I add my chems to bump up GH/KH and a heater to bring it up to tank temperature and let it mellow for another 24 hours.

Filling straight from the tap is a short cut and any short cut isn't without risk.


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## ncutler (Apr 26, 2010)

If there isn't any charcoal in the filter, you may want to add it. I had the same thing happen and as they said above, it turned out that I had just used carpet cleaner and it was on my hands when I went to fix a plant. Charcoal removed it quickly. Lost 11 fish though to that mistake.


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## neven (May 15, 2010)

darb said:


> kinda sounds like gas bubble disease to me.
> 
> If you filled directly from the tap that would be my first guess. It is more of a problem as the water temperature drops in the reservoirs.
> 
> ...


Is that when a fish dies and you see air bubbles under the skin?


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## Fish Whisper (Apr 22, 2010)

White Blisters, that sounds familar to when my Tank crashed.

In my case i also did a large water change, due to temperature differnce of the water added it killed the Nitrosamous..Nitrifiing (ammonia eating) bacteria.

This caused a huge spike in Nitrate/Ammonia, causing flesh burn, sad sight to see. 

Maybe another factor killed the bacteria in the filter, causing water to go bad.
-time taken from when the filler was turned off
-GH booster, if in powered form was it pre-dissolved, or if added directly to tank could some it been taken up by filter. (shocking ur bacteria colony)
-foreign chemical, Soap, bleach, residual hand cream.

Its important to remember that not only the fish is alive in a Tank Eco system.


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## darb (Apr 21, 2010)

neven said:


> Is that when a fish dies and you see air bubbles under the skin?


yes and it also explains the red spots, smaller gas bubbles would cause tissue damage which again would cause hemorrhaging.

all probably preceded by erratic behaviour by the fish as it would be fairly painful.


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## katienaha (May 9, 2010)

I have seen white blisters/skin peeling off the fish, but the only thing that died from it was BN plecos and pearl gouramis. dwarf neon rainbowfish and all but one zebra danio lived through it. no one could figure out what it was.. I was using tons of dechlorinater, and eventually i gave up and started dosing pure tea tree oil... I didnt buy any new fish for 2 months, let everything settle, and then added a pearl gourami, it did just fine, so I restocked and everything is great now. I still dont know what killed my fish...


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## Dosan (Sep 15, 2010)

Sorry to hear about your losses. I lost quite a few fishies on a W/C some weeks back and I still don't know what killed them. Hope things get better for you soon.


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## ngo911 (May 19, 2010)

darb said:


> kinda sounds like gas bubble disease to me.
> 
> If you filled directly from the tap that would be my first guess. It is more of a problem as the water temperature drops in the reservoirs.


Hmm that's interesting... I fill straight from tap and havent had a problem yet. Are you saying this could be an issue during the winter months?


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## Morainy (Apr 21, 2010)

Thank you for your ideas and help, everyone. These were my fish. A sad accident.


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## hgi (Jun 13, 2010)

Morainy said:


> Thank you for your ideas and help, everyone. These were my fish. A sad accident.


:O busted!

Sorry to hear for your lost, I've done worse.... Back in the day when I didn't know anything about fish tanks I decided to clean out my gf's fish tank for her since it was on a window shelf getting direct sunlight. So I put all the fish in a bucket with about 20% of their water, and scrubbed the tank and filters with dish soap.... Yep, the tank looked great for the rest of the day but the fish all died very quickly


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## Immus21 (Jun 14, 2010)

I have always filled directly from the tap as well. No problems with gas bubble disease. I don't see how it could be considered a risk but then again maybe I've kept hardier fish types.


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## Sandy Landau (Jun 4, 2010)

So, I think that I've finally figured out what I did, that killed the fish. Does this sound likely?

After changing the water, I decided to add some Excel and fertilizers. I put 3 caps full of Excel into the tank, which was about right according to the instructions. But now I'm thinking that it wasn't Excel that I added, but Replenish, which raises gH. The bottles looked identical. And I'd already added Replenish to raise the gH. So, I must have added way too much, causing an instant huge spike in the hardness of the water.


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## darb (Apr 21, 2010)

Three caps doesn't sound like a lot, what size tank was it going into, how much of an OD would this be? This also would have caused a PH swing if it was an overdose though. Personally I still suspect GBD, the blister is a classic sign. Run the cold water tap for a while to make sure that you are getting fresh cold water from the water main, fill up a glass and let it sit on your counter overnight. You may be surprised by the amount of bubbles that form on the sides of the glass.


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## big_bubba_B (Apr 25, 2010)

darb said:


> kinda sounds like gas bubble disease to me.
> 
> If you filled directly from the tap that would be my first guess. It is more of a problem as the water temperature drops in the reservoirs.
> 
> ...


if u add the prime before u add water . it wont hurt the fish filling it from the tap i have never ever had a problem . its persons prefrence . not write or wrong .


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## darb (Apr 21, 2010)

big_bubba_B said:


> if u add the prime before u add water . it wont hurt the fish filling it from the tap i have never ever had a problem . its persons prefrence . not write or wrong .


Prime does nothing to address the dissolved gas in water.


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## Sandy Landau (Jun 4, 2010)

Yes, it could also have been gas bubble disease. I let each bucket stand for more than an hour before tanking it and there were no bubbles on the glass but I did change nearly half the water in the tank. In fact, half if you don't count the gravel. Gas bubble disease compounded by Replenish poisoning.

I can tell you one thing, I am never going to change someone else's tank water again, especially unasked!


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