I was changing half the water today in my tank, and My Betta fish Alli and other 2 x-ray tetra were fine. Then i looked back at them a couple hours later and I only had 1 tetra left! I spent 15 minutes looking in my 3.5 gallon tank, so that doesnt leave very many places for the fish to go. He isn't there anywhere :(. So is it possible that my female betta ate and swallowed my tetra? she chases them around and taunts them every now and again, but i never thought she would do that. I made sure i took out my filter and looked in it, and it is completely clean. No tetra in the filter, but i dont want to think about my betta killing and eating one of my tetras :( can someone please help at all?