Please forgive me if this is in the wrong section; it is my first post on the forums.
I love the "plakat" look (short tail) that some betta have. A small business in my area specializing in tropical and marine fish order in betta directly from breeders in Singapore and thailand. Because of that, they get all sorts of betta variations. I bought one that caught my eye. It was a solid blue colour with a black head (typical colouring) but it had short fins and looked like a plakat.
The reason I think he is an Imbellis (peaceful betta) is because he does not attack anything or flare up often. He lives in a 25 gallon aquarium with a bunch of community fish. I added a crown tail into the tank out of curiousity, and the short fin did not mind in the least. The CT flared and became aggressive at him, but the short fin didn't do a thing. The CT has of course been removed and put back into his own 5 gallon tank.