Its my red zebra, he was fine one day, I come home and now he swims oddly. He acts normal, but when he swims he wont use his back tail fin w/e you wanna call it.... it looks no so spread out anymore... and he's the mean one of the tank - no one picks on him and he doesnt looked nipped at soooo.... I dont know whats up with him?? anyone know or have this problem before?? He's eating normal and doesnt seem very bothered... he just swims at the bottom now.... I put him in a hospital tank for now...