4 Fish DIED during water change

[SKEET]

3 tiger barbs and my rainbow shark . Used my Python, sucked out about 75% of the water (as usuall) and while the new water was going in those fish started acting funny and within 3-4 minutes, tank is full and fish are dead. I treat the water little by little as it is refilling via the Python, all of these steps have been the way I have done water changes daily for a longe time now.

Any ideas.

 

[rich311k]

Was the temperature close? I assume the KH in tap and tank are close. You are sure you use dechlor and not something else by accident?

 

[Fishyfanatic]

What was the temp of the water that you were adding? Are there any survivors?

 

[SKEET]

The temp difference is usually only 2 degrees and my tap water PH readings run between 7.2 and 7.6, one time 7.8.

All other fish are doing fine all day long.

 

[Fishyfanatic]

What was the temp difference during the last water change? You said "usually only 2 degrees" but what was it today? Could be stress. What are your water readings?

 

[SKEET]

Just tested as follows---- Ammonia < 0.25 , Nitrite NO2 0.25 , PH = 7.6

I dont know about the exact water temp when I did it, just remmember the digital read out going up some, it must of been about usuall because I didn't give it any concern.

 

[DeFeKt]

de-chlorinator doesn't work straight away
my guess is the chlorine from a 75% water change is the culprit.
fair enough successfull previously, but things change. levels change.
the addition of an ammonia level indicates the fish were probably stressed at the time, a swing in water chemistry from the water change could have been the culprit after that.

 

[SCFatz]

If I had to guess I'd say the tank was stressed do to 1ppm nitrite (.25 after the change),and that coupled up with temp change did it.

When dealing with a cycling tank its important to keep your levels down and match your temps closely....the stress is there before the PWC do to water quality (hence the big change)....an acute temp difference on top of that is asking for trouble imo.

I move a suction cup thermometer into the sink and get the water to within 1 degree before I start filling the bucket...the idea being that the new water helps the levels,but is otherwise unnoticed.

 

[Lonewolfblue]

I'm thinking more towards nitrite. The reason being, when I do a PWC, as long as the temp coming out of the python is within 3-4 degrees, there won't be much of an affect on the fish. I don't go to the extent of using a thermometer and getting the temp to within a degree. It's unnescessary. And I've never had fish losses due to PWC's. Even large 80% PWC's. As long as the temp is within 3-4 degrees, it won't affect the fish at all.

 

[SCFatz]

I probably go above and beyond with the temp a bit...but it gets fabulous results lol.

My only point is a big water change was done for a reason.That coupled with a temp change (which we don't know how large) may be the culprit.

In an establised tank those flucuations may be fine because its the only issue......in a cycling tank its a new issue,on top of the reason for the large change.

Just my thought on it....if cycling with fish,match temps closely.

 

[Fishyfanatic]

I still think it is the stress of the increased levels in combination with the temp swing. Dechlor works instantly. Most individuals add the dechlor after the water has been added (or during the change). Even with the most sensitive fish it does not harm them.

 

[DeFeKt]

Dechlor works instantly.

Let me get this straight...
you add dechlorinator and it somehow mixes with 100% of your water molecules instantly ?

I was not aware of that.

Tops !!

 

[Alshain]

Dechlor works instantly.

Let me get this straight...
you add dechlorinator and it somehow mixes with 100% of your water molecules instantly ?

I was not aware of that.

Tops !!

Let me clarify. Depending on the size of your tank, it works within a minute or two. Fish can tolerate the chlorine and chloromines for that long. When I do my PWC, I don't add dechlor until I'm finished completely. By then its been in the tank for 5-10 minutes, another 2 isn't going to hurt that much. The point is, the molecular bond is instant and with good circulation, the dechlor moves around the entire tank rather rapidly.

 

[malkore]

It wasn't the chlorine/amine IMO. Like SCFatz said, if you had .25ppm of ammonia and nitrite after the w/c, then you had at least 1ppm of each before the water change. 1ppm of ammonia is enough to cause damage...1ppm of nitrite is enough to cause respiratory issues.

those were the 3 weakest tiger barbs in the school I'm sure...so slightly malnourished.


since we're talking about adding dechlor during the filling, I add my dechlor when I begin to refill the tank, all at once, at the filling point. I figure the current from filling mixes the dechlor around so it can work.

and plants are more affected by chlorine than fish, and my plants look fine, so I know a good dechlor like Prime works quickly enough to not be a concern as long as you're adding enough to treat all your chlorine.

 

[SKEET]

That ammonia level is less than 0.25 ( < 0.25 ), for the last couple of weeks it has stayed very low and sometimes zero , and the NO2 doesn't get as high now for 3-4 days, after the fish deaths that AM I tested at 10 PM and got those readings ( amm less than 0.25 and NO2 at 0.25 ). That ammonia was probably below 0.25 beforre that water change is what I'm getting at and the test later still showed just a hint of ammonia ( not quite the yellow = 0 )

I bet they were weak from that on slaught of NO2 I was batteling and finally succumb to it.

Is the best way or most common way to add the de-chloranater to put the full dose amount in the tank before the water goes in??

 

[joannde]

On the bottle of Prime it says to dose for the whole tank if you're doing a partial water change and not adding the product into a bucket with the water before it goes into the tank. Don't know the answer if you're using something other than Prime.

 

[Lonewolfblue]

Also, it doesn't matter when it's put in. You can put the dechlor in before, during, or right after filling. I personally start filling, then I'll dose for the whole tank all at once.

 

[Jaybird]

I don't dose for the whole tank. I did a 50% PWC yesterday in my 90G and as I was putting the water in via the python, I added a capful of Prime. One capful treats 50G, and I was only replacing 45. I've never lost fish due to a PWC.

I have lost fish during the cycling process, but that was before I knew about fishless-cycling.

My guess is that if you are getting ammonia and nitrite readings, your tank has not completely cycled. That will stress the fish, and if people are correct about the temperature difference of the water that was put into the tank, it could have been the final nail in the coffin.