Fish Deaths

[GerardK]

A day after a partial water change, a procedure I have done dozens of times, I came home to find that every fish had died. what is the most likely cause, water temperature or chemicals in the water?

 

[Castellop123]

Did you add dechlorinator... What percentage of the water did you remove...

If you did not add dechlorinator to the tap water and nothing had happened in the past... then maybe your water supplyer JUST started adding larger amounts of chlorine and chloramines to their water... Full answer... do not know, many possibilities...

 

[WILDER]

Yes it could be that, or something like a household chemical got in the tank.
R.I.P.

 

[GerardK]

I always add dechlorinator and bring the water to an equal temperature to the tank water. what is the best way to cleanse the tank and its contents?

 

[WILDER]

Salt water then rinse well.

 

[confusion]

I read a lot of forum postings (here and other places) about heaters going crazy and cooking the fish. My guesses would be:
- failed heater
- unknown chemical got into the tank and poisoned the fish
- suffocation from lack of oxygen. a power outage could have left your fish with no air.