I have not had any luck with bettas recently. My one fishy died Christmas Eve after his fin was turning white. I treated him with aquarium salt but he ended up passing away.
Then, just 2 days ago my mom and I took a little road trip to Petco so I could see different tail types and pick out a new fish. Well, I fell in love with 2 fish, a white crowntail with teal and a double tail with red fins and a body that changes color from green to purple. It wasn't until I got home and put the crowntail in his tank that I noticed he had trouble swimming. I think he had swim bladder. I fasted him and treated with Epsom salt but he died just a few hours ago.
Going back tomorrow to Petco to return him, wish I could give him a proper burial.
Thank goodness my double tail seems to be healthy. I just hope I have better luck with him. I've kept bettas before in less water with no heater and they lived 2-3 years. Now I try to give a better life with proper heating and room to swim and they die.