Hello all ! Upon getting ready for feeding, me and my boyfriend did a head count and...one of our tetras is just gone? No body. We've looked in, under, around, over, everything. Nothing. And it wasn't even one of the small ones. What happened?? We have, well had, 6 neon tetra, 2 sunset platies, and a very docile elephant ear betta male. They've never shown any sorts of aggressive signs or any sickness. We monitor our readings weekly and change water 25 to 50 percent depending on said readings, weekly.