The leader of the school of barbs is a female, she's the biggest in the tank and has dropped eggs before. Vertical swimming is normal when they sleep, but the past few days she's been doing it during the day for 5-10 seconds randomly, almost as if she's falling asleep mid swim. Also some erratic swimming, and her color fades a bit. She's active and swims away if I come to the tank, and eats just like she always does. She seems healthy, but is this some sort of breeding/pregnancy behavior?