Fungus gnats are small (1/8 inch long), black, and have large, green eyes. They often fly in swarms and are most easily identified by their small size and their green eyes.
The best way to get rid of fungus gnats is to eliminate their food sources by thoroughly cleaning your kitchen and bathroom. You can also use commercial fly traps or bait. If you have a severe infestation, you may need to call a professional exterminator.