Koshmar
The Hardy Mongolian Pony
Sorry for your loss, I don't know what I would do if one of my little buddies died.
A little tip is to use white vinegar to clean the outside of the tank and the feeding stick/tongs/baster. Remember that a lot of cleaning solutions are volatile and can creep into a room, especially when the a/c and fans are on. When I clean my bathroom (just down the hall from my tanks), I turn off the ceiling fans just in case. Nitrites were probably the cause though, I always make sure mine are zero, my nitrates are another story though.
I still do weekly water changes to keep them down.
You will get another one and next time you will be fully prepared. Try not to beat yourself up too much. Time to start over. We're here to help.
A little tip is to use white vinegar to clean the outside of the tank and the feeding stick/tongs/baster. Remember that a lot of cleaning solutions are volatile and can creep into a room, especially when the a/c and fans are on. When I clean my bathroom (just down the hall from my tanks), I turn off the ceiling fans just in case. Nitrites were probably the cause though, I always make sure mine are zero, my nitrates are another story though.

You will get another one and next time you will be fully prepared. Try not to beat yourself up too much. Time to start over. We're here to help.