We don't have fire ants, but I remember my parents talking about them when the lived in Florida. Fire ants can be beneficial. They eat ticks, fleas and other pesty insects, but are considered a pest themselves because of the danger they pose to other species of animals and to humans. Their venom is highly concentrated and stings are painful.
Today I came across an informational site about the fire ant. The site gives background and history on the ants. It also provides ideas about controlling them. If you have fire ants, you may want to check it out.