I got everything (fish, tank, decor) 4 days ago. I think since I added everybody at the same time he feels like the space is not his. The only threat is his reflection...lol. Sometimes I go to check on him and I can't even find him. I'm glad his behavior is normal. This is my first betta in almost 10 years.
I think the new tank might have something to do with it. I've had some flare like crazy the first week in their tank and then calm down. They're claiming their new territory.
Some people dislike them flaring at their reflection too much, though, and put white paper over three sides of the tank to minimize reflections... That never worked for me, though, because then he'd just flare at me, lol.
Rusty my veil-tail betta does the same thing and it's usually in the same far right hand corner. I am wondering if it has to do with light glare that he thinks another fish is after his territory. Our fishes due the darnest things. This is why we love them so much.
I'm flattered that it is normal. Elfy cost me a pretty penny. More than I would normally spend on a fish, but his beauty captivated me and drew me in. Hubby wasn't too happy that i went to buy dog food and came back with a whole new aquarium fish and all. He wasn't amused at all and as I was setting up the tank and conditioning the water, he said coldly, "Wasting my money." LOL....he got over it the 3rd day in.