Black Fly


Actual Size: 1 to 5 mm

Characteristics: Black with some gray markings or reddish coloring.

Legs: 6

Antennae: Yes

Wings: Yes

Habitat: Drawn to environments near slow-moving water such as creeks, streams, or rivers.


  • Needs gently flowing water to reproduce. 
  • Females are blood-feeders and will readily bite people or other animals. 
  • Bites can trigger a reaction called “black fly fever”.

Black Flies in Anaheim

Also known as turkey or buffalo gnats, black flies are a common pest in several parts of Canada and the United States. These pests have an annoying habit of flying around people’s heads and sometimes crawling into their ears, eyes, or hair. Female black flies also need a blood meal before reproducing, so they can be aggressive toward humans and animals. These flies are most active in late spring and early summer, and can appear in very large numbers during the warm months of the year.

Black Fly Habitat

Black flies need running water to lay eggs. The larvae and pupae thrive in non-polluted water with high levels of dissolved oxygen, which is why people mainly discover these flies near slow-moving streams or rivers. Lakes and ponds rarely have enough movement for these flies to develop. Adult males and females primarily feed on nectar, though females will also consume blood before producing eggs.

Black Fly Behaviors, Threats, or Dangers

It’s never fun to deal with black flies while trying to enjoy time outdoors. Though they’re not known to transmit diseases to humans in the United States, their bites can still cause reactions ranging from a small puncture wound to swelling the size of a golf ball. Some people may also experience headaches, nausea, fever, and swollen lymph nodes after a bite, which is known as “black fly fever”. Additionally, black flies can transmit nematode worms and protozoa to livestock, which can make them dangerous near farms. 

Keep seeing black flies on your property? You don’t have to struggle with these pests every summer. Call your local fly exterminators to get rid of black flies quickly.