Madagascar Hissing Cockroach

🔤 Taxonomy

Gromphadorhina portentosa is the accepted scientific name for the Madagascar hissing cockroach. The genus contains several similar hissers, and hobby colonies are sometimes mislabeled or hybridized with G. oblongonota or G. picea. Obtain stock with a traceable identification if pure species matters.

Common names include Madagascar hissing cockroach, Malagasy hisser, and hisser. “Giant hissing cockroach” is not sufficiently precise for identification.

📌 Description

This is a large wingless forest-floor cockroach, usually 6-10 cm long. Both sexes force air through abdominal spiracles to hiss when alarmed; males also hiss during courtship and territorial encounters. Mature males have pronounced bumps on the pronotum and hairier antennae, while females have a smoother pronotum.

Hissers are hardy and observable, but the colony still needs secure housing, clean food, moisture, ventilation, and population control. They can climb smooth surfaces and small nymphs exploit tiny lid gaps.

Care point	Practical target
Adult size	6-10 cm
Lifespan	2-5 years
Small colony enclosure	about 45 x 30 x 30 cm
Temperature	24-28°C; night 20-24°C
Humidity	60-75% with ventilation
Diet	varied plant foods plus a moderate dry staple

🌍 Distribution

Gromphadorhina portentosa is endemic to Madagascar. It is associated with sheltered forest-floor microhabitats, leaf litter, and decaying logs, where it feeds on fallen and decomposing organic material.

Captive and laboratory colonies now occur worldwide. That introduced captive distribution makes containment important even where outdoor winters seem too cold for permanent establishment.

Range map

⚖️ Legal status

Checked on 2026-08-22: Gromphadorhina portentosa is not listed in the CITES Appendices, no species-specific listing was found in the EU wildlife-trade annexes, and the Bern Convention is not relevant to this non-European species.

Live cockroaches can nevertheless be controlled by local or national agricultural, import, transport, landlord, school, or public-display rules. Keep the invoice, breeder and colony-line details, scientific identification, and any import or transfer paperwork. Check both origin and destination rules before shipping; never release animals, nymphs, unwanted substrate, or enclosure waste outdoors.

🤌 Husbandry

A secure 45 x 30 x 30 cm enclosure is a practical starting point for a small colony of about six adults. Increase floor area, hides, and food stations as the population grows. Use a tight lid with fine secured ventilation, because adults climb glass and plastic and newborn nymphs pass through coarse mesh.

Quarantine new stock for 60-90 days with separate tools. Note sex ratio, births, molt quality, feces, odor, and mites. Do not combine seller lines until identification and health are clear.

💡 Lighting

UVB is not required. Provide a 10-12 hour room-light cycle and many dark retreats. Avoid direct sun and strong display lamps; hissers are mainly nocturnal and small containers overheat quickly.

Red or very dim observation light can reveal activity after dark, but it should not add meaningful heat.

🌡 Heating and temperature

Maintain 24-28°C for steady activity and breeding, with a cooler retreat around 20-24°C and a night range of 20-24°C. Colonies survive cooler rooms but grow and reproduce more slowly. Avoid sustained temperatures above 30°C.

If heat is required, place a thermostatically controlled source on one outside wall so the colony can move away. Measure temperature inside near the warm hide and at the cool end. Never put the enclosure in sun.

💧 Humidity and water

Aim for 60-75% humidity with part of the substrate slightly moist and the surface allowed to dry. Briefly higher humidity supports nymph molts, but persistent condensation, wet egg cartons, or sour odor means ventilation or cleaning is inadequate.

Supply moisture through fresh vegetables and a very shallow water dish with stones or another textured exit. Replace water daily. Sponges and water gels become contaminated unless changed and cleaned frequently.

🌿 Enclosure and decoration

Use 5-8 cm of pesticide-free topsoil, coir, decomposed leaves, or a blended forest-floor substrate. Add cork bark and vertically arranged egg flats to expand retreat space. Keep cardboard away from the dampest corner and replace it when soiled or soft.

Containment details matter:

use fine metal or securely bonded mesh
keep bark and cartons below the lid
test cable and door gaps against newborn nymphs
use a removable petroleum-jelly barrier near the upper inner rim if necessary
open the colony inside a larger sorting tub

🪳 Feeding

Offer a varied plant-based diet and a modest dry staple. Suitable foods include leafy greens, carrot, squash, sweet potato, apple, pear, banana, and other clean produce. A whole-grain insect diet, fish flakes, or balanced dry feed can add protein, but large amounts of dog or cat food quickly foul a warm colony.

Use shallow dishes and remove fresh food within 24-48 hours, sooner in heat. Food must be pesticide-free. Do not rely on lettuce or watery fruit alone; variety supplies more useful nutrients and keeps the colony from depending on one seasonal food.

🥚 Breeding

This species is ovoviviparous: the female retains the ootheca internally and gives birth to live nymphs. At warm stable temperatures, gestation is about 60 days and a brood commonly contains 15-60 young. Nymphs mature in roughly six to seven months.

Breeding is easy enough that population planning is part of basic care. Separate sexes if offspring cannot be housed responsibly. A female may already be gravid when purchased, so a female-only group is not an immediate guarantee against births.

🩺 Common problems

Escapes: coarse mesh, warped lids, and hides touching the roof are the usual routes.
Mold and odor: remove wet food, reduce crowding, replace soiled cardboard, and improve airflow.
Molting injury: maintain access to moisture and avoid handling pale, newly molted animals until the cuticle hardens.
Mites: Gromphadorholaelaps schaeferi commonly lives on hissers and is generally regarded as a commensal cleaner, not a blood-feeding parasite. Heavy mite loads still justify better hygiene and less wet food; do not use pesticides on the roaches.
Allergy and irritation: cockroach debris can trigger allergy, and leg spines can scratch. Wash hands, avoid touching the face, and use gloves if sensitive.
Poor reproduction: cold conditions, an all-male group, crowding, dehydration, or chronic disturbance can be responsible.

📌 Conclusion

The Madagascar hissing cockroach is a strong first display-invertebrate colony when containment is taken seriously. Set the adult population limit and plan for live-born nymphs before purchase; an easy-breeding species becomes difficult once every secure enclosure is full.