He might just need a little bit of time. My crowntail took about 5 days before he turned into a prima donna. He just kind of sat on his heater for the first 2 days after he explored, then he floated around a bit for the next couple days. They take a little bit to turn into proper bettas.
Proud mom of Samuel, the red, white and blue VT and Darius, the purple and red HM.
Samuel's Tank Mates:
4 peppered Cory Cats
1 Siamese Algae Eater