The survivors of a vicious fox attack that killed almost half of Melbourne Zoo's little penguin population on Tuesday night remain in isolation as measures are taken to hunt down the culprit, which returned to the scene of the slaughter last night.

New security footage shows the marauding fox returning to the penguin exhibit, which is one of the zoo's most exposed, the creature apparently still hungry after the massacre of 14 penguins.

The 15 survivors of the attack have been moved to a secure location onsite, as have the zoo's quokkas, which were also deemed at risk of attack from the voracious intruder, which is believed to have breached the grounds sometime in the past week.