I’m just saying when my last Betta passed away, I found his skeleton the next day. The snails and shrimp had already eaten most of him, but I still found it.You can believe it or not but the bones of small fish are not very substantial. You will never see a guppy or Betta skeleton. I really do think those shrimp ate the whole fish bones and all. You ever see snails on a dead fish ? They leave nothing and a shrimp is a better scavenger than a snail.
There’s no sign that he died in there, which makes me think he might have jumped… but I can’t find anything outside the tank.