definately possible, especially because most bettas are so used to small quarters that they seem to not always adjust to larger spaces right away. Another issue I've found, is that when you first put them in a larger tanks, and even more so if it has a filter, their fins get really thin and may start to go ragged. As long as you keep things clean so they don't get fin rot, they'll grow back and be much stronger thouhg.
Don't know if anyone else has had that experience, but it's happened pretty reliably to every single betta i put in a larger tank w/ filter regardless of gender.