When the Spooner family returned from holiday they were woken in the night noise from the kitchen.
"We actually thought there was someone in the house and looked around everywhere - then we went into the kitchen and the fish food was gone."
The family suspected an animal but said the cat door was locked and no cat was found in the house.
At more than $10 a pop for the disappearing fish food, the family turned pet detectives to find the thief.
"We set up the Ring security system from our front door and used blue-tac to secure containers of fish-food to the bench," Spooner said.
And the thief took the bait.
"We heard another noise early hours of the morning and went and checked the footage and there it was - a video of this lovely looking white fluffy cat on the bench."
The family searched the house expecting to find the cat but it had escaped.
"It's a clever cat because the only way out was through the cat door that is locked and has a magnet.
"It's figured out how to pull it open and somehow take the food with it."
The Spooners have taken to Facebook in the hope someone recognises the fluffy feline.
"So far we have a few suspects lined up but no clear lead," Spooner said.
"Someone must be at home wondering where all these containers of fish food have come from."