I just added a new betta to my divided 10 gallon. He came from a pet store in a little cup, and was surrounded by other males, so he evetually got used to seeing other males. I have a background on the tank that shows his reflection when the light is on, and he flares at it constantly. He even flares at the sides of the tank that don't have the back ground. It's funny though that he has yet to really flare at his neighbor through the divider, while the neighbor (who rarely flares at his own reflection) flares at him. The new one has only been in the tank for about 24 hours, but I don't want him to be too stressed out. WHen should he start settling down? He ate his pellets on his first night, so no problems feeling at home lol.