I got my female betta as a baby and raised her in a 1 gallon kept at 82 degrees with two silk plants with water changes every other day. I purchased her in September so she's probably 10-11 months old. I've always planned on moving her to my 5 gallon marineland eclipse when she got big enough. She is now big enough so I set up my 5 gallon with two filters, both at a very low flow and heater at 82 degrees.
Anyway, when she was in the one gallon she was very friendly. She would always come out when I entered the room and follow me and beg for food. Ever since she's been in the five gallon (2 days) she darts away at the sight of me! Do some bettas just need time to get used to their new surroundings? She has two silk plants to hide in. All other behavior as far as eating and her physical appearance are normal aside from what I've read are stress lines.
I'm hoping she just needs a few days to scope things out. Has anyone ever experienced a fish enjoying smaller spaces?