Five hamsters died in a fire which broke out in a house at Mangotsfield near Bristol on Saturday night.
It is believed that a tea-light candle, burning in an upstairs bedroom, set light to some paper.
An Avon Fire Brigade spokesman said crews stopped the flames spreading downstairs, but much of the first floor is badly damaged.
Red Cross volunteers and the social services are said to be working to help re-house the family.
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