HELP! Fish rapidly dying after a water change!!!

[daisy531]

I have a 10 gallon freshwater tank for 2 months with 2 zebra danios and 2 mickey-mouse plattys. Last water change was a little over 2 weeks ago. I just vacuumed half the tank, scrub the decor, and changed about 40% of the water but about 15 minutes later I look over and one of my danios was freaking out! A minute later it started to float to the top upside down struggling around the tank and 5 minutes later it completely stopped moving and got stuck to the filter. Once i gave it a nice funeral my other danio started to freak out too but chilled out after a few minutes. My plattys are alright but they do seem a bit slower than usual, what did I do wrong? Sorry this is so long but I love my fish so much

[mimiheart]

I had a similar thing happen after a water change a couple months ago. Still don't know what happened, but usual suspects:

Did you dechlorinate the new water/use conditioner? Was the temperature the same? What's the nitrates/nitrites/ph of the new water? There could be a wild swing in the source water that could cause something weird happening. Did you turn off your heater/filter/etc while changing the water? Check to make sure there are no leaks. Did you have anything on your hands that could have gotten into the water? (Soaps/detergents/alcohol/poisons?)

[daisy531]

First off thanks for replying I really appreciate it! And I responded yes to every question (nitrates and other variables are stable) besides the water temperature, I had to run somewhere and let it sit for 20 minutes so I didn't really check if it was the exact same as the tank, maybe it was that, the danio that died also didn't eat today so maybe it was too weak to take the stress, I will never take that risk again with my fish

[mimiheart]

Freak things happen. I lost all of my serpaes and two tiger barbs at once, and I still don't know how. (I think it was something in the substrate that got stirred up during the change, but I have no idea.) Same water going into two different tanks, one tank everything died, the other everything was fine. Good luck!

[daisy531]

Thanks Mimi!!!