My boyfriend had 2 syndontis catfish and I went to his house one afternoon and looked and there was only one. No places to hide. It was a completely empty 10 gallon tank. No decorations. Just the filter and heater. We looked all over the counter and he was getting frustrated and I happened to glance down at the floor a few feet from the tank and I yelled:
"SYNODONTIS ON THE FLOOR!!!"
Funniest moment ever, but for the fish who by then was crispy and dry and very much deceased. I still joke with him and shout that saying. It sounds like we discovered an ancient dinosaur species or something.
I figured what happened was he had scooped out a dead fish about 18 hours prior. It was a cichlid that got mauled by the older cichlids and didn't survive his injuries.
We think the synodontis got stuck on the net when he pulled it out. He said where it was on the floor was about where he was standing. His syndontis are only babies so not very big. They also have slightly prickly fins that probably got tangled in the net hence getting pulled out and falling on the tile floor.
He was actually able to exchange the dead one for another one so he has 2 of them again. He still had his receipt from time of purchase.
So who knows. I doubt you accidentally scooped your poor missing fish out. It's probably more like my otto story where my otto just disappeared and I later discovered his remains while doing the gravel cleaning.
But I had to share that story with you nonetheless. I love to give my boyfriend a hard time about it.