Bluebottle vs Green Bottle Flies – What’s the Difference?

Bluebottle and green bottle flies are often mistaken for each other. Both are metallic, both are loud, and both are drawn to decaying organic matter — but they are not identical.

If you’re seeing large shiny flies around bins, kitchens, or commercial food areas, it usually indicates a nearby breeding source. That could be food waste, animal faeces, or in some cases a dead rodent in a wall or loft void.

Understanding the difference between bluebottle and green bottle flies helps you identify the likely source faster — and remove it properly.

Below, we explain how to tell them apart, the health risks they pose, and how to deal with infestations in London & Essex homes and businesses.

What Is a Bluebottle Fly?

Also known as Calliphora vomitoria (yes, it sounds as bad as it is), the bluebottle is one of the most common blowfly species in the UK.

Appearance:

• Metallic blue body
• Around 10–14mm in length
• Large red eyes, black legs
• Loud buzz due to larger body and wings

Behaviour:

• Drawn to rotting meat, faeces, and carcasses
• Lays eggs in decomposing matter or bin waste
• Common around outdoor bins, compost, and butcher counters

Risks:

• Spreads E. coli, Salmonella, and other dangerous pathogens
• Cross-contaminates food and surfaces in seconds

Fact: A single bluebottle fly can carry over one million bacteria on its body.

What Is a Green Bottle Fly?

Green bottle flies (Lucilia sericata) are slightly smaller but just as hazardous.

Appearance:

• Metallic green body
• Around 10–12mm in length
• Red eyes, black legs, and a distinctive mid-range buzz

Behaviour:

• Also feeds and breeds on rotting organic matter
• Found near carcasses, waste bins, and open wounds
• Known to infest wounds in animals (myiasis)

Risks:

• Spreads bacteria
• Strongly attracted to decaying rodents or birds hidden in walls or lofts

Fun Fact: Green bottle fly larvae are used in maggot therapy to clean infected wounds in hospitals — but they’re not welcome freelancing in your home. NHS Source

Key Differences: Bluebottle vs Green Bottle Flies

Feature	Bluebottle Fly	Green Bottle Fly
Body Colour	Metallic Blue	Metallic Green
Size	10–14mm	10–12mm
Buzz Sound	Loud and deep	Mid-range pitch
Common Locations	Bins, meat counters, carcasses	Gardens, lofts, carcasses
Pathogen Risk	Very High	High

Signs You’ve Got a Bottle Fly Problem

• Persistent buzzing near windows or bins
• Sudden fly clusters in lofts, attics, or boiler cupboards
• Maggots appearing in unexpected places
• Increase in flies after a bad smell (dead animal, food spill)

Heads up: Dead rodents in wall voids are one of the top causes of bottle fly infestations.

How to Prevent Bottle Fly Infestations

✅ Keep bins sealed — indoors and outside
✅ Clean up food and drink spills immediately
✅ Disinfect kitchen surfaces regularly
✅ Use fly screens on windows and vents
✅ Inspect for hidden dead animals in voids and lofts

Bugwise Fly Control Services in London & Essex

If flies are making a scene — we’ll clear it up.

At Bugwise Fly Control, we go beyond sprays and swats. We identify the source, treat the problem safely, and give practical hygiene guidance to stop it coming back.

Our fly treatment includes:

• Rapid-response inspections
• Safe insecticide application
• Dead animal detection and removal
• Commercial and residential cover
• Ongoing advice for hygiene & prevention