Such a beautiful fish! I would name him after something else you enjoy! I love pokemon so I'd name him Onyx as he is black like the stone but so cute like a pokemon lol. I usually use names that sound strong and powerful to try and help my fish live as long as they can =] just my 2cents
If you haven't got a name yet, I would suggest calling him Fawkes.
Fawkes is the highly intelligent phoenix in Harry Potter - the animal companion
and feisty defender of Dumbledore. All traits that suit our beloved bettas lol
The gorgeous black and flame colouring resembles a phoenix too.