Hello, and welcome to the forum. :)
To start of, there are no "breeds" in bettas... There are only fin and color varieties. Such as fancy mice. They're all the same except color and covering look. There are different species as in betta imbellis and betta smaragdina.
He is an obvious elephant ear. (Also known as "dumbos" or EE) His fins are pretty long to be a PK so I'm guessing HM or S/DeT. Only time will tell. :p
Keep his water really clean and give him high-protein foods like frozen BBS as Laki has said. He should feel better once he's settled in. IAL (indian almond leaf) will prevent infection. If you're in the tropics, you can easily find it in parks or outside your house.
Over hundreds of bettas die in their small, dirty cups each day. Only you can help them live. Research and then save them, today!