I know its not exacted related to betta's, but my power went out last night, and my filter isnt pumping now. I cant seem to fix it. It's going, but its not pumping.
Sometime you only have to add water , or work the intake pipe up and down.
Next I would check and see is the intake pipe is plugged. Check , see if your impeller is pluged .
Unit pluged in , got elec to filter ?
You probably allready did all this, but it's all I can think of.