I was wondering if someone might know if there was any significance to something I've seen my BA tetras do. I've got 8 Ba's and sometimes late in the eveningh they all go to one corner of the tank. They float about 2/3rds of the way down, & then 1 or more, even all 8, will swim straight up almost to the top of the water. Then they'll float back down & start over. They'll do it for about 10-15 minutes, then breakup and swim around the tank.