Everytime I feed this happens..they eat for about 2 minutes and then get right next to each other so that they are touching side by side and smack each other with their tails, bite, then fly around the tank taking everybody out. Used to just be with blood worms but now is with every kind of food. Dont think its a big deal really but everyone else is calm and eating and literally get run over if they arent dodging. They are both about 5-6 inches, one much thicker than the other. Odd behaviior and dont know why.