I have fleas indoors. I'm fighting them with borax sprinkled all over the floors (messy, but effective. You can buy 20 Mule Team Borax laundry booster at the grocery store), vacuuming a lot, washing rugs, and little bowls of water setting around a lamp on the kitchen floor (they are attracted to the light, hop into the water, and drown) and of course I've treated my cats with Advantage. But mystery, I walk outside in my white socks, walk all around in front and back, and get no fleas. I did adopt a cat who was living in the woods (I live in the woods, too), but if he brought them in, where did he get them that I can't find them?

Do fleas have any natural, botanical predators, like ants and termites do (nematodes)? I'd love to have chickens and ducks to eat the ticks -- not sure if they could find the fleas -- but I'm afraid coyotes and raccoons would get them. IF I even have fleas outside!

I wish there were a natural predator for fleas! To fully rid your house of fleas, not only do you need to use the borax, but also vacuum everything that could possibly hide a flea or an egg and then throw the bag away - far, far away. You will probably have to repeat this cycle several times to totally get rid of fleas. Do you have indoor companion animals who suffer from fleas? If you do, then i suggest a systemic flea repellent like sentinel (for heartworm and fleas) and, if your animal friends are canine, give them brewer's yeast and garlic to help them stay flea-free!
Good luck!

Are you using chemical insecticides in your yard? If your are, you may be killing the ants that eat fleas and making your problem worse. Ants have a lot of uses and do not need to be killed unless they are causing a problem you can't tolerate. DO NOT use systemic products on any of your animals. Would you want poisons inside of your body? Use Munster pet food for your pets and it will help. Check the website for additional help. Stay natural !! Hopefully someone will provide additional info.

Beneficial nematodes apparently work outdoors.