Just about an hour ago I moved my betta from a half gallon to a five gallon, and he is going nuts! He just swims around like his tail's on fire in circles around the tank, stopping at points to wiggle back and forth. The temperature I don't think has changed a whole lot, but I do have some water and gravel from an established tank in there. I acclimated him before putting him in. I have a filter, but I built a baffle, so the current doesn't look so bad. I fed him a bit and he seems to still be a pig.
My concern is:
Is he okay? What is going on and should I be worried?