They're beautiful. Just don't skimp on the water changes suggested here. In a tank that size, more is more. Set yourself a strict schedule and stick to it like glue. Welcome to the forum! Happy betta keeping. :D
ahhh your fish are gorgeous!!! where'd you get them? i have 3 bettas each in 1 gal tanks, i'm pretty tight on space too. they're all very active and i keep mini post-it notes close by to remind me for water changes, and after i do them i pre-set the water for the next change.