Pretty boy. (: Multicolor crowntail.
The mark looks just like coloring to me. I haven't tried the type of food you have, I use New Life Spectrum, which is a pellet variety.
Tank size looks great.. you're going to need to pick up a heater for him to keep the water at 78-80* this winter, since bettas are tropical fish. Also, check the plants and decoration for sharp edges, plastic plants are notorious for catching and tearing a betta's fins.. if you can at some point, upgrade him to silk (or even live if you can manage it).
Otherwise looks pretty good, welcome to the forums. (: