Hello, I have some questions about my tiger barbs. First, one of my tiger barbs disappeared and me and my dad looked all around the tank for him. We lifted up both of the decor pieces and nothing. We also didn't see him floating near the filter or anything.So, do tiger barbs eat each other? He was not sick or anything too.Also, are tiger barbs known to swim in place at the top of the tank, were the water level stops?Also my bleeding heart tetras swim at the top too.It's weird. Thanks!