My Betta Ryu has some funky habits. I found out by accident something amusing. I tried the mirror trick to get him to flare, but he ignored it. One day I was talking (during which I wave my hands often) and suddenly he flared!
After experimenting I found that "wiggling" my hand in a "vertical wave-like" motion made Ryu flare. Now we exercise that way sometimes... The scary, but inda cute one is his sleeping. As soon as the light goes out he hides in his stone structure and "sleeps." The scary part is he flops over and floats inside it. I swore he was dead the first few times. I would rush over and literally had to gently SHAKE him out of it.... He gave me the grumpiest look ever, moped around for a bit, and went back in it... The most amusing part of this is that when I first put that piece in the tank Ryu was scared to death of it. Never a dull moment with that fish.