Fleas vs Gnats vs Lice

Whats The Difference Between Fleas & Gnats & Lice?

Fleas, lice and gnats are not the same thing. This article aims to highlight some of the differences so that you can determine the cause of your problem. The table below is comparison using pictures and basic information.

cat flea
  • 1/16 to 1/8 of an inch in length
  • Dark reddish-brown
  • Flat with 6 legs
Fleas prefer to reside on their warm-blooded hosts. They can also be found on clothing, bedding and furniture. Clothing and pets can transfer the fleas to different hosts. Fleas can jump about 8 inches and 16 inches horizontally.
  • Itching of dogs & cats
  • Bite dogs and sometimes people

fungus gnat
Image credit:UMN.edu
1/8 of an inch long but varies depending on the flyAttracted to damp soil in house plants and other areas with moisture such as bathrooms, sinks & drains
  • You will notice them flying & crawling on counters
  • Flies do not bite
louse image
  • 3/16 of an inch long
  • Light brown, red or tan
Found together in large numbers. Reside inside & outside. Can be transmitted on humans and animals depending on the type.


Fleas are a parasitic insect, 94% of fleas feed on the blood of warm-blooded animals.

Cat Flea
Cat Flea

Adult fleas are generally found on furniture, bedding, in the yard or hidden behind protected areas such as baseboards. If your pet scratches chronically it may be a sign of an infestation. Treating your pet directly is not enough. Your home must also be treated inside and out to prevent future infestations.

Fleas lay between 300-800 eggs in a 21 day gestation period. Eggs may fall off the host causing infestations to be greater in areas frequented by the host. Fleas live for a year on average and have been known to spread diseases such as Typhus and the Plague. This is largely due to the fact that over 75% of flea species are associated with Rodents.

Fleas are known to carry many diseases, so continuous irritation of the skin maybe a sign that the host has fleas. It is important to make sure that any persons or pets that show sings of being infected and checked by a doctor. Do not let any pets roam into densely wooded areas, if so check fur for any fleas, the same for people before entering the home. Clean sheets, pillows, cloths and other fabrics and textiles to help minimize the possibility of an infestation and the likelihood of spreading it. If in infestation does occur treatment of the house and hosts are necessary.

More information about flea control.


Gnats is a term commonly used to refer to a few kinds of flies. There is no specific gnat species. Gnats are usually one of the following:

Fungus Gnats

Fungus gnats are some of our tiniest flies, with thin, dark bodies that end in a point and a pair of tiny, clear wings.

adult fungus gnat
Image credit: NC State

They have no ability to bite or otherwise harm us, but if the conditions are just right for them their numbers can grow to very high levels.

As nearly all flies do these gnats undergo a life cycle that begins with eggs deposited by the adult flies. Since the larvae will feed on mildew and fungi of some sort the adult flies look for the damp conditions that will grow this food resource. The eggs hatch to the larval stage and the larvae progress through several stages, feeding on the fungus around them. Finally they change to the pupa stage and then emerge as new adult flies. The life cycle can be a rapid one for these small insects. When everything is perfect – plenty of food, a warm setting – the complete cycle from egg to adult fly can happen in less than 2 weeks, so a rapid buildup of gnats can occur quickly.

Inside the home a common place to find perfect conditions for fungus gnats will be house plants, more specifically the soils these plants grow in. We have a tendency to love our plants too much, and commonly over-water our plants, keeping the soil wet continually. The soils usually are high in organic matter, and this combination of moisture and organic matter is a perfect invitation for fungi to grow. It does not necessarily have to be a big mushroom growing up out of the soil, as the gnat larvae are tiny, and will find the minute bits of fungus growth within that medium. Allowing the soils in these pots to dry out on a regular basis is not only a good way to prevent the growth of fungi and fungus gnats, but it may also be better for the plants themselves.

Drain Flies

The drain fly is also called a “moth” fly because it may resemble a tiny, gray, hairy moth.

Drain Fly
Image credit: Matt Bertone, NC State

We can recognize them as flies, though, by the single pair of wings, whereas moths have 2 pairs of wings and look very different.

The drain flies are usually no larger than about 1/8 inch long, with their thorax and wings covered with gray hairs. They fly in sort of a zig-zag motion and often then just PLOP down onto a wall or door. They may be found commonly in bathrooms, as this is where a lot of moisture exists that may attract them. When they are sitting on a surface they hold their wings flat over their abdomen.

Why They Prefer Drains
Unlike the fungus gnats, which manage to breed in simply damp conditions, the drain flies need a much larger buildup of material, and over time our sink, floor, or bathtub drains can provide this micro-habitat for them. As hair and many other things get washed into sinks there eventually will be an accumulation that could even become a complete plug in that drain. This area remains continually wet, with organic buildup coating the sides of the pipes below the sink, and drain flies look at this as just heavenly. Their presence in a room such as the bathroom is a sign to you that some cleaning is necessary, and that is really how the control of drain flies will be accomplished.


louse image
Size: Lice are small, usually 1/8 to 1/4 of an inch long.
Color: light brown, light red, or tan in color

Head Lice

Head lice (Pediculus humanus capitis) are tiny wingless insects about two millimetres long which live on the scalp and neck of humans. When an infestation occurs there may be up to 12 adult lice on the scalp at any one time. They feed from human blood and must eat at least twice a day; they cannot survive for more than one day at room temperature off a human body. A female louse can lay eggs at the rate of about six per night up to a total of 100. The yellow-white eggs, called nits, are stuck to the hair close to the scalp. As the hair grows, so the nits (or their empty shells) are carried away from the scalp and are more easily visible. Nits can often be mistaken for dandruff, flakes of dry skin or other small items caught in the hair.

Book Louse

Size: 3/16 Inches in Length
Color: Light Reddish Brown

  • Small wingless insect
  • Found outdoors or indoors
  • Lives in damp places
  • Frequently found in great numbers

Often found in tree bark, old papers, books and food products these pests enter your home when carried in on infested items.

More information about lice.