Fire services were alerted to the fire at Barr St, Balclutha about 2.20pm on Saturday.
Residents gathered on the footpaths to watch as smoke streamed from the roof of the two-storey brick house.
Balclutha woman Tossie Liebenberg said she was on her way back to Balclutha from Milton when she was contacted by her daughter to inform her about the fire in the house she rented with her husband and two daughters.
Two fire appliances from the Balclutha Volunteer Fire Brigade attended the fire.
Mrs Liebenberg said she was shocked when she was first told of the fire.
None of her family were in the house at the time of the fire.
One of her cats was rescued by firefighters and handed to her from the veranda. She was relieved and grateful her two cats were found alive although one had gone missing in the afternoon.
Firefighters also rescued the turtle from its tank.
Mrs Liebenberg said it was "very lucky" no members of the family were in the house at the time.
Normally, her daughters did not want to travel to Milton, where she and her husband were flying model planes, yet the youngest came along.
Her other daughter was out with friends when normally she would have been at home.
Balclutha Chief Fire Officer Graeme Ferguson said it was unclear what caused the fire. A fire investigator was sent to the scene to determine how it started.
Mr Ferguson confirmed one cat was rescued and the other, which firefighters had seen, had since gone missing. He did not believe it was caught in the fire.
There was extensive damage to the kitchen and the rest of the house had considerable smoke damage, he said.
Fire crews arrived at the scene shortly before 2.30pm and took 30 minutes to extinguish the fire.
