Water Change Fish Died

[Stephan]

Nephew did a water change today and all but a few red tail sharks died. What can cause this?

 

[This Old Spouse]

Did you use dechlorinator when replacing the water?

 

[Stephan]

Sorry just reported with more details when I didn't see my post.

He didnt dechlorinate until after he filled up. Would that get them that fast?

 

[KittyKat]

More details at http/www.fishforums.net/index.php?/topic/366398-water-change-fish-dead/