The fire took place in a home on Sanford Place in Bridgeport while the resident was not at home, said the Bridgeport Fire Department.
Officials say they believe a hoarding condition inside the apartment helped fuel the flames.
Firefighters said two cats inside the apartment perished while firefighters were able to save another with the help of oxygen.
The apartment received minimal damage.
Click here to follow Daily Voice Bridgeport and receive free news updates.