The fire broke out at Jon's Exotic Pets in Rising Sun, Cecil County, just before 8:00 p.m. Wednesday.
Firefighters found smoke billowing from inside the pet store when they arrived.
70 firefighters were called to help fight the blaze including a crew from nearby Chester County, Pennsylvania.
Inside were an assortment of dogs, cats, birds, chinchillas, rabbits, and reptiles.
Only three animals survived the blaze.
It's unclear what caused the fire.
Five adults and one child who lived in the apartments above the pet store were forced out due to smoke damage.
None of them were hurt.