Recently, I got a Nemo tank decoration since my little sister wanted it to go in the betta tank because she thought he needed a friend. When I put it in, my betta Furry (sister was also the one who named him and said he looked furry, so the name stuck), he fanned out his fins and gills and started flapping them in the fake fish's face and trying to intimidate it and bite it. He has been doing it multiple times a day, every day. I read that bettas can get stressed out whenever they see themselves in the mirrors, and doing that too much can cause harm. My family members said he'll be fine and that if he is capable with being around other tank mates (although he is solitary at the moment), he can be around a fake fish. Is the fake Nemo fish going to cause him stress over time? And if so, could it lead to over aggressiveness and self-harm?