Marble's not so much his name as his colouring type. I tend not to name my bettas. Each one gets called "the new betta" for a few days, then it gets shortened to "the betta". Or sometimes Mr Fish.
I have folders with pics of each different betta, and the folder name is the type of betta. The last one's folder was 'blue plakat', the one before was 'dragon'. The new one's folder is called 'marble' so the pics are named marble 1 and marble 2 for now.
He is a marble, which means he has blotches of different colours. With this colour type, the patterning and even colour changes as the fish matures and then ages, so it will be interesting to see how my new fish alters over time. As you can see in the pics, he currently has a red head and pale blue/white everywhere else. He was in the section labelled as half moon bettas, but he isn't a half moon. I think he's probably a delta tail, I'll wait a few days for him to settle then see if I can get him to flare (using a mirror) which will show what his tail type actually is.
He's now out of the bag and exploring
I got him from the Maidenhead Aquatics about 3 miles away, a shop I don't usually visit. Two reasons - it's smaller than the one 10 miles away, and until a couple of years ago it was not an MA. There was a fish department in the garden centre, run by them, and it had a bad reputation. The garden centre has since changed hands and the fish dept is now an MA but I still can't bring myself to get fish from there after a few bad experiences under the previous owners. But this fish is in a tank on his own so he won't kill any other fish. (I once bought some dwarf pencilfish from there and put them in with my pure bred endlers. Within 48 hours all the pencilfish and all the adult endlers were dead. Only the fry survived. On another occasion, the new fish brought in a resistant strain of whitespot that took 3 courses of treatment to eradicate).
Resa - yes, I do prefer plakats, the problem is finding any