Sorry for your lose, but glad to hear that you got a new one...
I have a betta fish, but not that big. He's red. I had a little scare a few months ago where he just stopped swimming and was on the bottom, but the next day he was up and swimming again... weird. I got him last December. He's my first betta after 3 goldfish that died 3 days after i got them.
. I didn't think my betta would last this long. lol. I first named him Rosie because I thought he was a she but then I looked at a chart and found out that she was a he and renamed him Ricky.