Cory death after PWC, what happened?

[Squall]

So I just did a 50% PWC on my 10 gallon planted. About 5 minutes after the water change, I noticed one my cory habrosus not moving on the bottom, on his side, and eventually was dead .

I had 6 of these wonderful fishes in the tank, now down to 5, all of which were active before and no issues whatsoever.

I have 2 suspected reasons why it died, but I want to ask you guys what you think might have happened.

- My 1st hunch is the cory died of oxygen overdose , if there is such a thing. I was filling up the tank straight from the tap using my gravel hose, it's a small gravel vac which the tube fits the faucet. The tank is placed on top of the kitchen counter so the faucet is accessible. The flow of the water causes enormous amount of microbubbles that filled the tank. I noticed my cories were darting to the surface to breath during the time I was filling the tank. They did not do it the 3 previous times I did PWC the same way.
- My 2nd hunch is, I made a mistake of putting prime after almost filling the tank with water . The cory might have died of chlorine poisoning.

The tank is fully cycled. I always make sure that when filling the tank that the temperature of the water is almost the same through feeling (which I always do even with my 60 gallon). The remaining cories are somewhat inactive right now, and I am afraid for the worse. So what do you guys think happened? What might I have done wrong?

 

[NYgiantsRP]

Well I dont agree with either hunch. I have never heard of a fish having too much oxygen. I have had corys with multipule air strips, plus at the same time dumping water in the tank, and there was tons of bubbles, nothing ever happened. Also I have done 75% water changes and forgot to put the water conditioner it it for hours, and nothing ever happened. Maybe i was just lucky. It could have been the stress of the water change. If the fish was already weak, or was stressed from something else could have been the "straw that broke the cammels back" type thing.

What kind of corys are they? 6 in a 10 gallon seem like too many.

 

[Squall]

Well I dont agree with either hunch. I have never heard of a fish having too much oxygen. I have had corys with multipule air strips, plus at the same time dumping water in the tank, and there was tons of bubbles, nothing ever happened. Also I have done 75% water changes and forgot to put the water conditioner it it for hours, and nothing ever happened. Maybe i was just lucky. It could have been the stress of the water change. If the fish was already weak, or was stressed from something else could have been the "straw that broke the cammels back" type thing.

What kind of corys are they? 6 in a 10 gallon seem like too many.

They are cory habrosus, a type of dwarf cory. You are right, it might have been stress since they were all active cories before the PWC. But this is the 4th time I did the PWC the same way.

 

[GodFan]

Let me ask this, when was your last PWC? I have found (through expierience) that waiting too long on water changes can cause this but not because of what you think. The fish may adapt to the lesser water. Then by adding new water you drastically change the parameters stressing the fish.

 

[smileyface9]

I think it was cause the clorinated water was added straight to the tank. On mine i put it in a bucket, declorinate with a conditioner, check the ph, then add it if it's right. Even though it's more work it keeps fish alive and less stressed by re-adding water a little slower by taking your time. Try that on your next water change and see how you like that.

 

[Squall]

Let me ask this, when was your last PWC? I have found (through expierience) that waiting too long on water changes can cause this but not because of what you think. The fish may adapt to the lesser water. Then by adding new water you drastically change the parameters stressing the fish.

I do my PWC every 6 or 7 days.

 

[Squall]

I think it was cause the clorinated water was added straight to the tank. On mine i put it in a bucket, declorinate with a conditioner, check the ph, then add it if it's right. Even though it's more work it keeps fish alive and less stressed by re-adding water a little slower by taking your time. Try that on your next water change and see how you like that.

I do it it all the time, putting Prime directly to the tank, which I believe is ok as far as some posts here suggest. What I was thinking was I did put the Prime a little bit late, when I should have put it before filling up. I also do it always with my 60 since I use the Aqueon water changer with it with no problems.

 

[GodFan]

I do it it all the time, putting Prime directly to the tank, which I believe is ok as far as some posts here suggest. What I was thinking was I did put the Prime a little bit late, when I should have put it before filling up. I also do it always with my 60 since I use the Aqueon water changer with it with no problems.

I add my prime after I fill the tank and know of plenty of people that do as well. It shouldnt hurt the fish.

 

[Squall]

BTW, another 1 died this morning, so that leaves me with 4. This is the 1st time I had multiple deaths for an unknown reason. I am now thinking it could have been the stress with the water change. But I filled up the tank real slowly and did put the prime even it was a little bit late. These is disappointing not to know what is the real reason. I will probably go back with a bucket when I do the PWC on this 10 gallon next time.

 

[Ardynas]

Do you think it could be Ph shock?

I put tap water directly into my tank too but always put the Prime in first before refilling.

 

[smileyface9]

Do you think it could be Ph shock?

I put tap water directly into my tank too but always put the Prime in first before refilling.

Yeah, it was probably ph shock.

 

[smileyface9]

Do you think it could be Ph shock?

I put tap water directly into my tank too but always put the Prime in first before refilling.

Or maybe he needs the ph to be higher.

 

[jetajockey]

I don't really believe in pH shock but that's another subject in itself, it's probably not the problem unless you do water changes once a year.

It's possible that something else unknown is in the water. Is this municipal water or well water?

 

[Squall]

I don't really believe in pH shock but that's another subject in itself, it's probably not the problem unless you do water changes once a year.

It's possible that something else unknown is in the water. Is this municipal water or well water?

I also do believe that it's not pH shock since I have done PWC on this tank the same way from the same tap mulitple times now and 4 times using the gravel hose method I mentioned in my initial post. Its tap water and I do use it on my 60 as well without problem. Though it has 0.5 of ammo in it, but the tank is fully cycled and can handle it with Prime.
The remaining cories are doing well right now, eating and being active, and I have upped my stock to 6 again.
The thing I remembered when I was filling the tank was the cories started darting to the surface to gasp for air which they did not do during previous PWCs. That is why I suspected the microbubbles because it immediately clouded the tank and that is when I noticed the cories darting to the surface. I will go back to using bucket to this tank next PWC and see if they will react differently.

 

[jetajockey]

Well I've never heard of 'too much' oxygen. If anything, tap water tends to be low in o2/high in co2, which will cause fish to gasp after water changes briefly, but there is enough circulation in a normal aquarium to dissipate co2 and oxygenate the new water in short order.

 

[Squall]

Well I've never heard of 'too much' oxygen. If anything, tap water tends to be low in o2/high in co2, which will cause fish to gasp after water changes briefly, but there is enough circulation in a normal aquarium to dissipate co2 and oxygenate the new water in short order.

Maybe that was it, the water was low in oxygen during the filling that was why the cories were gasping for air. So my theory may have been the other way around. And that caused too much stress that led to the death of the 2 cories.

 

[smileyface9]

Maybe that was it, the water was low in oxygen during the filling that was why the cories were gasping for air. So my theory may have been the other way around. And that caused too much stress that led to the death of the 2 cories.

Very good point! i agree

 

[blert]

Just off the wall here but I'll throw it out anyway... Was there a 'boil water alert' going on for the day and time of the incident?

 

[Squall]

Just off the wall here but I'll throw it out anyway... Was there a 'boil water alert' going on for the day and time of the incident?

What is that boil water alert?

 

[blert]

What is that boil water alert?

They happen all the time. Your city water folks will issue them if there is a broken line somewhere or they have been doing repairs on the main water lines. It means that contaminants may have gotten into the water pipes so you are best off boiling your tap water so that you don't get sick or, God forbid, die from some funk that got in the water pipes.