Guys.... WE HAVE A SERIAL KILLER... :)
Another failure with same symptom, wire damage. Look closely at the wire few inches from the pump body, sign of being nibble.
This is the second pump that fail the same way in the same tank, never had happen before. The tank was not new and I had pumps in it before without any problem.
First it happen : Here as photo below.
Initially I thought it was the pump build quality, then could it be the wire chafe against the fibre tank. The pump has been use before and the tank is not new, no failure of this nature.
I know rats love to chew on wire, sometimes we can find them electrocuted while trying to munch through the insulator. But this wire is underwater, and rat don't do scuba dive.
One possibilities... its the Pacu that did it. Only this tank has Pacu fish and I only started doing pacu this year. I never had this problem before.
Wiki on pacu : Here
Photo above from the web of a Pacu fish.