Hey, do you still have a betta? You know that you can keep them without a filter and they will live for a long time. Or if you still have a filter really better to do more water changes than 25%. Clean the filter media as well. I just was erasing all confirmation mess's form the forum in my e mail and found your old post. Sorry for writing. Just hope you still have a betta. Who will rescue them if not we who love them Let me know if you need any help, my bettas live long, i can share my experience.