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German Cockroach

Blattella germanica

A small, light-brown cockroach that lives and breeds indoors, mostly in kitchens and bathrooms. It reproduces faster than any other household cockroach and is the species most often behind persistent indoor infestations.

Written by PestMan Editorial TeamTechnical review pendingPublished Updated
Size
10–15 mm
Key marking
Two dark stripes behind head
Lives
Indoors
Eggs per case
About 30–40

Questions about the German Cockroach

How to identify a German Cockroach

Identification

  • Adults 10–15 mm long, light tan to brown.
  • Two dark parallel stripes on the shield behind the head (pronotum).
  • Females often carry a light-brown egg case protruding from the abdomen.
  • Nymphs are dark with a pale stripe down the back.

Where it lives

  • Warm, humid indoor spots close to food: behind fridges and dishwashers, inside oven and microwave housings, cupboard hinges and under sinks.
  • Common in apartments, restaurants and other buildings with shared plumbing and walls.

Behaviour

  • Rarely lives outdoors in Australia; it depends on buildings.
  • Can fly only weakly, if at all; spreads by running and by being carried in boxes, bags and appliances.
  • Seen in daytime when populations are large.

Why it matters

A single female carries an egg case with around 30–40 eggs and can produce several over her life, so populations build quickly.

Some populations have become resistant to certain insecticides and learned to avoid some baits, which is why German cockroaches can be hard to control.

As an indoor species close to food, it is the cockroach most relevant to food contamination and allergies.

Commonly confused with

Australian Cockroach

Periplaneta australasiae

A large outdoor cockroach, despite its name probably not native to Australia. Common in gardens, mulch and around houses in warmer parts of the country.

Other cockroach species

American Cockroach

Periplaneta americana

One of the largest household cockroaches in Australia. Lives in drains, sewers and sub-floors and wanders inside on warm nights.

Oriental Cockroach

Blatta orientalis

A dark, glossy cockroach that prefers cool, damp places such as drains and basements. Less common in Australian homes than other large species.

Smokybrown Cockroach

Periplaneta fuliginosa

A large, uniformly dark mahogany-brown cockroach that lives in trees, roof voids and gutters and is a strong flyer attracted to lights.

Guide

The Australian Guide to Cockroaches

Everything an Australian household needs to know about cockroaches: which species you are seeing, why they are there, how they get in, the health implications, and how to prevent and manage them.

Guide

How to Pest-Proof Your Home

A practical, room-by-room approach to reducing pests without relying on chemicals: remove what attracts them, close the ways in, and make your property less comfortable for them.

Guide

Common Brisbane Household Pests

A Brisbane-specific overview of the pests residents meet most often, when they are active, and what the subtropical climate, storms, creeks and Queenslander homes mean for pest pressure.

More about cockroaches

Cockroaches

Fast, flat-bodied insects that hide in warm, damp gaps and come out at night to feed. A few introduced species cause most household problems in Australia.

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Sources & further reading

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