I.D. the Ant
Keep it Clean to Deter Ants
A clean house is your first defense against ants. Sweep up food crumbs, wipe up spills, take out the garbage and don't leave dirty dishes sitting around the house. This takes away the ants' food source. Spray vinegar mixed with water around bowls of pet food to keep ants from feasting there.
Erase Ant Trails
Where you see one ant, you're bound to see others. That's because ants leave a scented trail that other ants follow. Sweeping or mopping isn't enough to eliminate the scent. Instead, mix 1 part vinegar with 3 parts water in a spray bottle, then spray wherever you've seen ants in the past. This will stop outdoor nesting ants that entered the house to forage for food (ants that come inside are not necessarily trying to establish a nest).
Vinegar and water won't stop ants that are already nesting indoors. You'll need to kill them with ant bait.