He's a beauty. I'm a bit rusty on my betta terminology, but I believe his fin style is called a halfmoon rose tail not a double halfmoon. Rose tail refers to the ruffle-y/ragged appearance of the fins. He doesn't look like he has a double tail from the picture, but the double portion of the name would mean that his tail is split in two. The dumbo part only refers to the pectoral fins being larger than normal, giving the fish the appearance that it has dumbo ears
I would just take care of him, being in a 10g with clean water and a filter will do way more for him than melafix or anything.
Ohh haha well I was just trying to say he will be a lot happier and healthy in a new tank, even my LFS keeps betas in tiny cups -.-...Melafix should never be used on bettas anyways... Theres been several reports that the oils can damage their labyrinth organ and cause them to drown. And besides, there doesn't appear to be anything wrong with his fins, they're supposed to look that way
Ohh haha well I was just trying to say he will be a lot happier and healthy in a new tank, even my LFS keeps betas in tiny cups -.-...