Fish do indeed look for food everywhere.
They will jump if they think something is edible.
Plus they will jump when spooked.
My O kept jumping lately after i did a wc.
Turned out there was a bit of ducttape loose above the waterlevel...
They're just curious and cannot oversee the risk of jumping.
On the other hand fish will jump if waterquality is bad.
Esp. catfish and plecos will try to bail a tank, and will look for a different environment if conditions are bad.
But your water is fine so that only leaves the first 2 options.
sorry for your loss.
Any ideas on getting a new fish?