Madagascan Hissing Cockroach (Gromphadorhina portentosa) Care Sheet
The Madagascan Hissing Cockroach is a large, wingless cockroach native to Madagascar and one of the best-known cockroach species maintained as a display invertebrate.
Unlike household pest cockroaches, Gromphadorhina portentosa is a specialised forest-dwelling species associated with decaying vegetation and organic material. Adults cannot fly, but they are excellent climbers and can scale smooth surfaces, including glass.
Their famous hissing sound is produced by forcing air through modified respiratory openings called spiracles. Males use hissing during territorial encounters and courtship, while both sexes and younger animals may hiss when disturbed.
They are generally hardy and straightforward to maintain, making them suitable for beginners, educational displays and established invertebrate collections. Successful husbandry requires warm temperatures, appropriate humidity with good ventilation, secure escape-proof housing, plentiful hiding places and a varied omnivorous diet.
Quick Facts
Scientific name: Gromphadorhina portentosa
Common names: Madagascan Hissing Cockroach, Madagascar Hissing Cockroach, Hisser
Family: Blaberidae
Origin: Madagascar
Adult size: Approximately 5–8 cm
Lifespan: Commonly around 2–5 years depending on conditions
Diet: Omnivorous/detritivorous
Activity: Primarily nocturnal
Lifestyle: Terrestrial and climbing
Experience level: Beginner
Wings: Absent in both sexes
Flight: No
Handling: Generally possible with care
Social housing: Yes, with appropriate colony management
Natural Distribution
Gromphadorhina portentosa is native to:
Madagascar
where it inhabits warm forest environments.
Wild animals are associated with:
- Forest floors
- Leaf litter
- Fallen logs
- Decaying vegetation
- Bark
- Organic debris
They spend much of the day concealed and become more active under darker conditions.
Appearance
Madagascan Hissing Cockroaches are large, heavily built cockroaches.
Adults typically display:
- Dark brown to black colouration
- Reddish-brown abdominal markings
- Broad flattened bodies
- Long antennae
- Powerful climbing legs
- No wings
Mature males possess particularly distinctive structures on the pronotum.
Adult Size
Adults commonly reach approximately:
5–8 cm in length.
Size varies according to:
- Sex
- Genetics
- Nutrition
- Developmental conditions
Large adult males can appear especially substantial because of their broad pronotum.
Wingless Cockroaches
Unlike many familiar cockroach species, both male and female Madagascan Hissing Cockroaches are:
completely wingless as adults.
They cannot fly.
However, their lack of wings should not lead keepers to underestimate their ability to escape.
Excellent Climbers
Hissing Cockroaches can climb remarkably smooth surfaces.
They can potentially climb:
- Glass
- Smooth plastic
- Silicone seams
- Enclosure decorations
A secure lid is therefore essential.
An open-topped glass aquarium is not escape-proof.
How Do They Climb Glass?
Their feet possess specialised structures that provide excellent adhesion to smooth surfaces.
This allows them to move across surfaces that many other terrestrial insects cannot climb.
Even relatively young nymphs may be capable climbers.
The Famous Hiss
The characteristic hiss gives the species its common name.
Unlike many insects that produce sound by rubbing body parts together, Madagascan Hissing Cockroaches create sound by forcing air through specialised abdominal:
spiracles.
The result can be surprisingly loud.
Why Do They Hiss?
Hissing can occur in several contexts.
It may be associated with:
- Disturbance
- Defensive behaviour
- Courtship
- Male territorial disputes
- Social interactions
Different hissing patterns may be used in different circumstances.
Disturbance Hiss
Both sexes can hiss when disturbed.
An animal picked up unexpectedly may produce a loud defensive hiss.
This does not mean it is preparing to attack.
It is primarily a warning or disturbance response.
Male Hissing
Adult males are particularly well known for vocal territorial displays.
Two males may:
- Approach one another
- Raise their bodies
- Push
- Ram with the pronotum
- Hiss repeatedly
These interactions help establish dominance.
Male Horns
Adult males possess prominent raised structures on the pronotum immediately behind the head.
These are often described as:
horns.
They are used during contests with rival males.
Females lack the same pronounced horn development.
Male Territorial Behaviour
Mature males may establish and defend preferred areas.
Male-to-male contests can involve:
- Hissing
- Shoving
- Ramming
- Raising the body
- Attempting to displace rivals
Serious injury is uncommon when sufficient space and hiding places are available, but overcrowding can increase conflict.
Lifespan
Madagascan Hissing Cockroaches are relatively long-lived for cockroaches.
A captive lifespan of approximately:
2–5 years
is possible depending upon:
- Temperature
- Diet
- Sex
- Genetics
- Husbandry
- Age at acquisition
Adults obtained from unknown sources may already be well into their lifespan.
Housing
Suitable accommodation includes:
- Glass terrariums
- Secure plastic tubs
- Purpose-built invertebrate enclosures
- Modified aquariums with secure lids
The enclosure should provide:
- Floor area
- Climbing surfaces
- Multiple hides
- Ventilation
- Warmth
- Appropriate humidity
- Escape prevention
Enclosure Size
For a small group, approximately:
45 × 30 × 30 cm or larger
provides a useful general starting point.
Larger colonies require more space.
Population density should be monitored because colonies can increase substantially when breeding conditions are favourable.
Secure Lid
A tightly fitting lid is essential.
Remember:
they can climb glass.
Check carefully around:
- Lid edges
- Ventilation panels
- Cable openings
- Sliding doors
- Feeding hatches
Nymphs can exploit smaller gaps than adults.
Escape Barriers
Some keepers use a smooth barrier around the upper interior of the enclosure as additional escape protection.
However, no barrier should replace a:
properly secured lid.
Barrier materials can degrade, collect debris or become ineffective over time.
Ventilation
Good ventilation is essential.
A warm humid enclosure without adequate airflow can encourage:
- Mould
- Mites
- Unpleasant odours
- Bacterial growth
The goal is a moderately humid environment with regular air exchange rather than a sealed wet container.
Temperature
A useful general temperature range is approximately:
22–28°C.
Warmer conditions generally result in:
- Greater activity
- Faster growth
- Increased feeding
- More frequent breeding
Cooler conditions slow metabolism and reproduction.
Breeding Temperature
Breeding colonies generally perform particularly well in the warmer portion of the normal husbandry range.
Temperatures around:
25–28°C
can encourage reproduction and nymph development.
Avoid uncontrolled overheating.
Heating
Supplemental heating may be unnecessary in a warm home.
Where additional heat is required, use:
- A thermostatically controlled heat source
- Gentle external heating
- Heating applied to only part of the enclosure
This allows the cockroaches to move between warmer and cooler areas.
Avoid Uncontrolled Heat Mats
Never use an unregulated heat source.
Small invertebrate enclosures can overheat rapidly.
Any supplemental heater should be controlled by an appropriate thermostat.
Direct Sunlight
Never place the enclosure in direct sunlight.
A transparent enclosure can become dangerously hot within a short period.
Keep the colony away from:
- Sunny windows
- Radiators
- Strong heat sources
- Extreme drafts
Humidity
Moderate humidity is appropriate.
A useful general target is approximately:
60–75% relative humidity
with good ventilation.
They should not be maintained in permanently saturated conditions.
Moisture Gradient
Providing a moisture gradient is useful.
One area can remain:
slightly more humid
while another remains somewhat drier.
This allows the cockroaches to choose their preferred microclimate.
Misting
Light misting can be used when necessary.
Frequency depends upon:
- Ventilation
- Temperature
- Substrate
- Ambient room humidity
Avoid continually soaking the enclosure.
Substrate
Suitable substrate options include:
- Coco fibre
- Fertiliser-free topsoil
- Soil/coir mixtures
- Naturalistic forest substrates
A layer approximately:
5–10 cm deep
is generally sufficient.
They do not require extremely deep burrowing substrate.
Leaf Litter
Leaf litter makes excellent surface cover.
It provides:
- Hiding opportunities
- Natural texture
- Humidity retention
- Additional organic material
Use only leaves collected from safe pesticide-free sources.
Hides
Provide numerous hiding places.
Suitable materials include:
- Cork bark
- Bark slabs
- Cardboard egg flats
- Cork tubes
- Lightweight wood
Vertical and horizontal surfaces can both be useful.
Cork Bark
Cork bark is excellent for naturalistic enclosures because it:
- Provides climbing surfaces
- Creates narrow retreats
- Resists decay
- Is lightweight
Stack pieces securely to create additional usable surface area.
Egg Flats
Cardboard egg flats are commonly used in larger breeding colonies.
They provide:
- Large surface area
- Numerous hiding spaces
- Easy colony access
- Lightweight structure
They should be replaced if they become heavily damp or mouldy.
Climbing Space
Although wingless, Madagascan Hissing Cockroaches climb frequently.
Provide:
- Cork bark
- Branches
- Bark
- Textured surfaces
Avoid unstable structures that can collapse onto animals.
Lighting
Specialist lighting is unnecessary.
Provide a normal day/night cycle.
Because the species is primarily nocturnal, they should have access to dark retreats during daylight hours.
UVB
UVB lighting is not generally required for routine husbandry.
If display lighting is used, ensure it does not:
- Overheat the enclosure
- Dry the colony excessively
- Eliminate shaded areas
Water
Clean water should always be available.
Because small nymphs can drown in deep dishes, use a safe arrangement such as:
- Very shallow dishes
- Water crystals specifically suitable for invertebrates
- Moist foods combined with safe water access
If using a dish, ensure all life stages can escape easily.
Water Crystals
Hydration gels or crystals are sometimes used in cockroach colonies.
If used, choose products specifically intended for feeder or captive invertebrates.
Replace them regularly to prevent contamination.
Fresh drinking water remains preferable when it can be provided safely.
Diet
Madagascan Hissing Cockroaches are omnivorous and consume a broad range of plant and organic foods.
A balanced captive diet should contain:
- Vegetables
- Some fruit
- Dry plant-based foods
- A modest protein component
Variety is important.
Vegetables
Suitable vegetables include:
- Carrot
- Squash
- Sweet potato
- Courgette
- Leafy greens
- Peppers
Rotate foods rather than offering the same vegetable continuously.
Fruit
Suitable fruits can include:
- Apple
- Pear
- Banana
- Melon
- Mango
- Berries
Fruit should be offered in moderation because sugary foods spoil quickly.
Banana
Banana is often readily accepted.
However, it can:
- Ferment rapidly
- Encourage fruit flies
- Attract mites
- Become mouldy
Offer only small quantities and remove leftovers.
Dry Foods
Dry foods can provide a convenient dietary foundation.
Options can include appropriate:
- Invertebrate diets
- Cockroach diets
- Grain-based foods
Avoid products containing excessive salt, artificial flavourings or inappropriate additives.
Protein
Some dietary protein is beneficial.
Appropriate sources can include small amounts of:
- Specialist cockroach food
- Suitable insect diets
- Other appropriate unseasoned protein sources
Excessive protein is unnecessary and may increase waste and odour.
Dog and Cat Food
Dog or cat kibble has historically been used by some cockroach keepers as a protein source.
However, a varied diet formulated around suitable plant foods and purpose-made invertebrate diets is preferable.
If animal feeds are used at all, they should be offered sparingly and removed if they become damp or spoiled.
Calcium
Unlike reptiles, Madagascan Hissing Cockroaches do not require routine heavy calcium supplementation.
A varied nutritious diet is more important.
Do not coat foods heavily in reptile calcium powder without a specific reason.
Foods to Avoid
Avoid:
- Salty foods
- Heavily seasoned foods
- Processed human foods
- Mouldy food
- Pesticide-contaminated produce
- Foods treated with household chemicals
Wash fresh produce before feeding.
Feeding Frequency
Fresh food can be offered:
several times per week
depending upon colony size.
Dry food can often remain available more consistently provided it stays clean and dry.
Remove fresh foods before heavy spoilage occurs.
Feeding Dishes
Shallow feeding dishes make maintenance easier.
They help prevent food from becoming mixed deeply into substrate.
Multiple feeding stations are useful for larger colonies.
Appetite
A healthy colony can consume surprising quantities of food.
Food requirements increase with:
- Colony size
- Temperature
- Number of growing nymphs
- Reproductive activity
Adjust quantities according to what is actually being consumed.
Nocturnal Activity
Hissing Cockroaches are primarily nocturnal.
They often become active shortly after the enclosure becomes dark.
Nighttime behaviours can include:
- Feeding
- Climbing
- Courtship
- Territorial interactions
- Exploration
Handling
Madagascan Hissing Cockroaches are generally tolerant of gentle handling.
They do not:
- Sting
- Possess venom
- Normally bite defensively
However, handling should remain calm and controlled.
How to Pick One Up
Whenever possible:
- Allow the cockroach to walk onto the hand.
- Support it from underneath.
- Keep the hand close to a safe surface.
- Avoid squeezing the body.
Do not pull a cockroach forcefully from a surface.
Strong Grip
The feet can grip skin surprisingly strongly.
If an animal refuses to release:
do not pull it by force.
Instead, allow it to walk onto another surface.
Pulling can injure the legs.
Hissing During Handling
A cockroach may hiss when first picked up.
This usually means:
it has been disturbed.
It does not necessarily indicate aggression.
If the animal repeatedly struggles or hisses, return it to the enclosure.
Defensive Behaviour
Their primary defensive strategies include:
- Hissing
- Clinging tightly to surfaces
- Hiding
- Remaining concealed
They are not aggressive animals.
Hygiene After Handling
Wash hands after handling:
- Cockroaches
- Substrate
- Food remains
- Enclosure furnishings
Cockroach colonies can contain microorganisms and allergens even when maintained hygienically.
Allergy Considerations
Repeated exposure to cockroaches and their waste can cause or worsen allergies in susceptible individuals.
Potential allergens may occur in:
- Shed exoskeletons
- Faecal material
- Body fragments
- Enclosure dust
Good ventilation and regular sensible cleaning are important.
Anyone developing persistent respiratory or skin symptoms around a colony should seek appropriate medical advice.
Moulting
Nymphs grow by periodically shedding their exoskeleton.
Immediately after a moult they appear:
soft and pale, often almost white.
This is normal.
Freshly Moulted Nymphs
A newly moulted cockroach should be left undisturbed.
Its new exoskeleton gradually:
- Hardens
- Darkens
- Develops normal colouration
Do not mistake a white freshly moulted individual for a different species.
Exuviae
The discarded exoskeleton is called an:
exuvia.
Cockroaches may consume some or all of their shed exoskeleton.
This recycles nutrients.
There is generally no need to remove fresh exuviae immediately.
Nymph Development
Young Hissing Cockroaches resemble miniature wingless adults.
They do not pass through a pupal stage.
Development follows:
Birth → Nymph → Repeated moults → Adult
This is known as:
incomplete metamorphosis.
Growth Rate
Growth rate depends strongly upon:
- Temperature
- Food availability
- Genetics
- Colony density
- General husbandry
Warmer well-fed nymphs generally develop faster than those maintained under cooler conditions.
Sexing Adults
Adult males and females are relatively easy to distinguish.
Mature males usually possess:
- Large pronotal horns
- Thicker, hairier antennae
Females generally possess:
- Smoother pronotum
- Less prominent raised structures
- Comparatively smoother antennae
Male
The adult male’s pronotal horns are the most obvious sexing characteristic.
They give the front of the body a distinctive raised appearance.
Males use these structures when competing with rivals.
Female
Adult females generally lack the large pronounced horns of males.
They often appear smoother across the pronotum.
Females can become noticeably broad when carrying developing young.
Breeding
Madagascan Hissing Cockroaches breed readily when maintained:
- Warm
- Well fed
- In suitable groups
No elaborate breeding setup is normally necessary.
Courtship
Males may:
- Hiss
- Approach females
- Display
- Compete with rival males
Courtship can be accompanied by considerable activity within the colony.
Reproduction
Madagascan Hissing Cockroaches are:
ovoviviparous.
The female forms an egg case called an:
ootheca
but retains it internally while the embryos develop.
The young are eventually born as live nymphs.
Ootheca
The ootheca may occasionally be briefly protruded from the female’s abdomen before being drawn back inside.
This can alarm inexperienced keepers.
Do not pull or manipulate a protruding ootheca.
Pregnancy
A gravid female may become noticeably broader through the abdomen.
Development of the young takes place internally.
Environmental stability is important during this period.
Live Young
Females give birth to multiple tiny pale nymphs.
The newborns soon darken and begin feeding.
They require essentially the same environmental conditions as adults but are much more capable of escaping through small gaps.
Nymph Escape Prevention
This is particularly important in breeding colonies.
Newborn nymphs are much smaller than adults.
Ensure:
- Ventilation mesh is sufficiently fine
- Lid gaps are minimal
- Cable openings are sealed
- Doors close tightly
An enclosure that contains adults successfully may not necessarily contain newborn nymphs.
Colony Housing
This species is well suited to group housing.
A healthy colony can contain:
- Adult males
- Adult females
- Nymphs of multiple sizes
Provide sufficient resources to reduce unnecessary competition.
Male-to-Male Competition
Multiple males can usually coexist when the enclosure provides:
- Adequate space
- Numerous hides
- Multiple feeding locations
Territorial disputes are normal.
Persistent severe harassment may indicate overcrowding.
Population Growth
A well-maintained colony can increase quickly.
Before breeding, consider what will happen to:
surplus offspring.
Potential solutions include:
- Expanding the enclosure
- Establishing additional colonies
- Responsible rehoming
Never release surplus animals outdoors.
Population Control
If reproduction needs to be limited, separating males and females is the simplest approach.
Remember that females obtained from mixed colonies may already have mated.
Population planning should begin before the colony becomes overcrowded.
Mixed-Species Housing
Mixed-species housing is generally unnecessary.
Do not house Hissing Cockroaches with predatory animals such as:
- Centipedes
- Scorpions
- Tarantulas
- Predatory beetles
These animals may attack or consume them.
Bioactive Housing
A naturalistic enclosure can include:
- Organic substrate
- Leaf litter
- Cork bark
- Safe plants
- Springtails
Bioactive housing can work well provided humidity, ventilation and colony cleanliness remain appropriate.
Springtails
Springtails can help consume:
- Mould
- Small food particles
- Decaying organic material
They are particularly useful in humid naturalistic enclosures.
They do not eliminate the need to remove spoiled food.
Mites
Small numbers of detritivorous mites may occur in cockroach colonies.
Large outbreaks are often associated with:
- Excess food
- Excess moisture
- Poor ventilation
- Accumulated waste
Correct the underlying conditions rather than using insecticides.
Never Use Insecticide
Cockroaches are insects.
This sounds obvious, but it is worth emphasising:
never use household insecticide anywhere near the colony.
Products designed to kill pest cockroaches can also kill captive species.
Cleaning
Routine maintenance should include:
- Removing spoiled fresh food
- Cleaning water dishes
- Removing excessive waste
- Replacing heavily contaminated substrate
- Cleaning feeding dishes
Avoid completely disrupting the colony unnecessarily.
Frass
Cockroach faecal material is commonly called:
frass.
Some accumulation is normal, but excessive frass can contribute to:
- Odour
- Allergens
- Poor hygiene
- Mite problems
Larger colonies require more frequent maintenance.
Deep Cleaning
A full enclosure clean may occasionally be necessary.
When cleaning:
- Transfer cockroaches to a secure temporary container.
- Check carefully for tiny nymphs.
- Remove heavily contaminated material.
- Clean using safe methods.
- Rinse thoroughly where appropriate.
- Ensure chemical residues are absent before returning the colony.
Never use residual insecticidal cleaning products.
Chemical Sensitivity
Keep the enclosure away from:
- Flea sprays
- Fly sprays
- Ant treatments
- Cockroach insecticides
- Aerosol pesticides
- Strong cleaning fumes
Even chemicals used elsewhere in the room may pose a risk.
Quarantine
New cockroaches should ideally be quarantined before joining an established colony.
Monitor for:
- Mites
- Unusual mortality
- Abnormal behaviour
- General condition
Quarantine is particularly useful when animals come from unknown sources.
Correct Identification
Several large Madagascan cockroach species are maintained in captivity.
Not every large “hissing cockroach” is necessarily Gromphadorhina portentosa.
Related captive genera and species can look similar.
Hybridisation within the hobby has also complicated identification of some captive lines.
Maintain breeder and provenance information whenever possible.
Captive-Bred Animals
Captive-bred stock should be preferred.
The species breeds readily in captivity, so there is generally little justification for unnecessary wild collection.
Captive-bred animals offer advantages including:
- Known captive history
- Reduced wild collection pressure
- Easier acclimatisation
- Better provenance where breeders maintain records
Responsible Sourcing
Before obtaining animals, ask about:
- Scientific identification
- Captive-bred status
- Approximate age
- Sex
- Existing colony conditions
- Diet
If establishing a breeding project, source accurately identified animals wherever possible.
Legal Considerations
Regulations surrounding non-native cockroaches vary considerably between jurisdictions.
Some regions restrict possession or transport because escaped cockroaches could potentially become:
- Agricultural pests
- Environmental pests
- Invasive species
Always verify current regulations before acquiring, selling or transporting the species.
Never Release Captive Cockroaches
Never release Madagascan Hissing Cockroaches outdoors.
This applies to:
- Adults
- Nymphs
- Unwanted colony members
If animals can no longer be maintained, arrange responsible rehoming.
Disposal of Used Substrate
Used colony substrate may contain:
- Tiny nymphs
- Shed exoskeletons
- Other invertebrates
Inspect it carefully before disposal.
Where escape or establishment is a concern, ensure no live cockroaches remain before discarding substrate.
Common Husbandry Mistakes
Common mistakes include:
- Using an unsecured enclosure
- Forgetting that adults can climb glass
- Using ventilation gaps large enough for nymphs
- Keeping the colony too cold
- Maintaining permanently saturated conditions
- Poor ventilation
- Allowing fresh food to rot
- Overcrowding
- Failing to plan for reproduction
- Pulling cockroaches from surfaces
- Using pesticides near the enclosure
Most problems are easily prevented with appropriate planning.
Are They Suitable for Beginners?
Generally:
Yes.
Madagascan Hissing Cockroaches are among the more forgiving large display invertebrates.
They are:
- Hardy
- Non-venomous
- Flightless
- Easy to feed
- Suitable for groups
- Relatively easy to breed
- Interesting to observe
However, secure housing and responsible population management remain essential.
Educational Value
This species is particularly useful for demonstrating:
- Insect anatomy
- Incomplete metamorphosis
- Sexual dimorphism
- Territorial behaviour
- Chemical-free sound production
- Detritivore ecology
Their size makes many anatomical features easy to observe.
Responsible Ownership
Before obtaining Madagascan Hissing Cockroaches, consider:
- Their ability to climb smooth surfaces
- Potential colony growth
- Need for warm conditions
- Regular fresh-food maintenance
- Possibility of cockroach allergens
- Requirement for secure nymph-proof housing
- Local regulations
- Long-term plans for offspring
They are straightforward animals to maintain, but a successful colony can become a very large colony surprisingly quickly.
Summary
The Madagascan Hissing Cockroach (Gromphadorhina portentosa) is a large, wingless cockroach native to Madagascar and one of the most recognisable display cockroaches in captivity.
Its famous hiss is produced by forcing air through specialised respiratory spiracles, rather than by rubbing wings or legs together. Adult males possess prominent pronotal horns and use hissing, pushing and ramming during territorial encounters.
Successful husbandry requires secure escape-proof accommodation, warm temperatures, moderate humidity combined with good ventilation, numerous hiding and climbing surfaces, clean water and a varied omnivorous diet.
Particular attention must be paid to enclosure security because adults can climb smooth glass and newborn nymphs can escape through surprisingly small gaps.
The species reproduces through retained oothecae, with females eventually giving birth to live nymphs. Colonies can therefore expand substantially under favourable conditions, making population planning an important part of responsible ownership.
Although generally tolerant of occasional gentle handling, these cockroaches do not require handling for their wellbeing. Their natural hissing, climbing, feeding, moulting and social behaviours make them interesting animals to observe without frequent disturbance.
With appropriate care, Gromphadorhina portentosa is a hardy, fascinating and comparatively accessible introduction to keeping large tropical cockroaches.
IMPORTANT INFORMATION
This care sheet provides general husbandry guidance and does not replace current species-specific research or applicable wildlife, agricultural and import legislation.
Several Madagascan hissing cockroach species and captive hybrids occur within the hobby. Confirm identification and retain provenance information whenever possible.
Cockroach colonies and their waste can contribute to allergic reactions in susceptible individuals. Maintain sensible hygiene and seek medical advice if persistent symptoms develop.
Never use household insecticides, flea sprays or other pesticide products near the enclosure.
Always verify current regulations concerning possession, breeding, sale, transport, import and export in your jurisdiction.
Never release captive cockroaches into the environment.
Information correct at the date of publication.
reptilecommunity.com | Revised: August 2026