The one-inch-long, fuzzy, red and black "ants" that you see are not fire ants. They are called velvet ants or cow killers in some areas but are actually a type of wasp. Males are winged, while females are not. They can inflict a painful sting but are not considered a pest. The females lay their eggs in bumblebee nests.
Many people assume that these big, red, stinging insects are fire ants. Fire ants are actually quite small (1/16 to almost 1/4 inch long), with the largest workers two or three times larger than the smallest. Sizes between different colonies can also vary greatly. Some mounds may have mainly small workers, while others may have more large workers. Queens are about 1/4 inch long.