Well this is a first for me. I Put the water changer in and than walked away while the tank drained and I came back to find my 3 year old female convict wedged in the tube. Lesson learned.
I did that with a beautiful baby super red flagtail prochilodous. Head got sucked in. When I tried to save him he was decapitated. For a second I thought maybe I could reattach his head. Lol.

Can you post a pic for us that have had decapitation issues? ? Great idea. Would like to see your example!I use a garden hose to drain my tanks. I cut a couple of v notches at end that goes into the tank. This way, even if a fish try to stick it's head into the house, there would be no suction seal...........or decapitation consequences
Damn!.......what a horrible way to go.I did that with a wakin goldfish once years ago. Sucked its guts right out of its butt. I felt awful. If she was bent I would euthanize.