Hey, it's not your fault! You didn't know better, and when you did you made an effort to change things. Sometimes these things happen. This weekend my household has lost SIX fish, and as I posted in this section I was about to give up. But DON'T feel that way, accidents happen a lot with fish, especially with new owners (like me). Is your crowntail still alive (sorry, I couldn't tell by what you said)? If so leave the filter out until you can figure something out. If not, I am so sorry for your loss. Since I am going through the same thing right now, feel free to talk to me any time.
Kindness and respect should be shown to all animals, no matter if they are furry, scaly, big, or small. Be a hero to the animals and GO VEGAN!