EMERGENCY fish dying after water change

[Hmontoya93]

Have you tested your water?

Yes

If yes, what is your ammonia?

0

If yes, what is your nitrite?

0

If yes, what is your nitrate?

15

If I did not test my water...

1. ...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

What percentage of water do you change?

51-60%

How frequently do you change your water?

Every week

If I do not change my water...

1. ...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

I have been doing water changes for years no issues did a big water change on 360 gallon maybe 200 gallons?
Everything was fine until I turned on the filter all my silver dollars spazzed out and died. I still have arowana and gar in there, is this PH shock ? I am not sure. I am scared to turn the filter on and loose more fish…



what is going on anyone have experienced this before?

This is my first big tank did I change to much ?

 

[Austin1234]

I had something similar happen once in a qt tank with my silver dollars. I had not planned on getting them so I was not prepared, filled a tank and put some est. media in and started the filter, several of the silver dollars went crazy the moment the filter came on and then died. I had a couple small Oscar’s with them that didn’t seem bothered at all. Have no idea what caused it though..

 

[Hmontoya93]

All I can think of was my water heater was changed recently maybe Gad in pipes for water ?

 

[tlindsey]

is this PH shock ?

Possibly
Did you check the temperature of the aquarium and water for refill during the wc.

 

[Hmontoya93]

I think it was maybe 4 degrees different, a little more than usual because of the weather

 

[Hmontoya93]

All other fish seem to have made it, including the regular silver dollars. Only the black bar school died

 

[tlindsey]

All other fish seem to have made it, including the regular silver dollars. Only the black bar school died

Some species of fish will be more sensitive to changes than others. How long have you had the black bar school. I know that most regular silver dollar species are captive bred and probably for years now.