Firebrat Care and Breeding Guide: How to Keep Thermobia domestica
If you're looking for a unique, heat-loving feeder insect that's easy to breed and maintain, firebrats (Thermobia domestica) might be exactly what you need. These small, fast-moving insects are closely related to silverfish but thrive in hot, dry conditions — making them a fascinating and practical addition to any feeder insect setup. At Thrive Ecosystems, we've been keeping and breeding firebrats for years, and in this guide, we'll share everything we've learned about firebrat care and breeding.
What Is a Firebrat?
The firebrat (Thermobia domestica) is a small, wingless insect in the order Zygentoma (formerly Thysanura). They're often confused with silverfish, but firebrats are distinctly different — they prefer much higher temperatures and have a mottled grey-brown coloration rather than the uniform silver of their cousins. Their name comes from their love of heat, as they're naturally found near furnaces, bakeries, and other warm environments.
Firebrats are an excellent feeder insect for small reptiles, amphibians, and invertebrates. They're soft-bodied, easy to digest, and their small size makes them ideal for juvenile animals or species that prefer tiny prey. They're also prolific breeders when kept at the right temperature, making them a sustainable and cost-effective feeder option.
Housing Your Firebrat Colony
Housing firebrats correctly is critical because they are excellent climbers on rough surfaces. Unlike many insects that can be kept in mesh-lidded enclosures, firebrats can scale cardboard, paper, and rough plastic with ease.
At Thrive Ecosystems, we house our firebrat colony in a 27QT Sterilite container with latching lids. The smooth interior walls prevent the firebrats from climbing out, and the latching lid ensures they stay contained. This is one of the most important setup decisions you'll make — don't use any container with a rough interior surface.
Substrate: We use dry Turface as our substrate of choice. Turface is a calcined clay product that stays dry, doesn't mold, and provides a stable base for the colony. The key word here is dry — firebrats do not tolerate humidity and will die off quickly in a moist environment. You can find Turface on Amazon or in our Supplies section.
Hides and Egg-Laying Sites: We use toilet paper rolls stuffed with expanded cotton balls as egg-laying sites. The cotton provides a soft, warm environment where females will deposit their eggs. Cardboard rolled into cylinders serves as hides, giving the colony places to shelter and reducing stress.
Ventilation: Unlike crickets, firebrats don't require heavy ventilation. We open the container 1–2 times per week to feed and check water levels, and that's sufficient. The goal is to maintain heat and dryness, so excessive ventilation can work against you.
Temperature: The Hotter, the Better
If there's one thing firebrats need above all else, it's heat. These insects are thermophilic — they thrive in high temperatures that would stress or kill most other feeder insects.
Your target ground-level temperature should be 95°F to 100°F (35°C to 38°C). We achieve this using a reptile heating pad placed under one side of the enclosure, creating a thermal gradient so the firebrats can self-regulate. It's important to place a barrier (such as a thin piece of wood or a folded towel) between the heat mat and the surface it sits on — this prevents heat from dissipating downward and ensures it's directed into the enclosure.
At temperatures below 85°F, firebrat reproduction slows dramatically. Below 75°F, they become sluggish and may stop breeding altogether. Keep them hot, and they'll reward you with a thriving, fast-reproducing colony.
Food: What Do Firebrats Eat?
Firebrats are omnivores and not particularly picky eaters, which makes feeding them straightforward. Our go-to food options include:
- Fish flakes — a high-protein staple that firebrats love
- Thrive Ecosystems Feeder Chow — our in-house formulated feeder insect food, available on our website
- Chick feed — an affordable, nutritious option available at most farm supply stores
Feed small amounts every few days and remove any uneaten food to prevent mold, which can be harmful in a hot, enclosed environment. Because firebrats prefer dry conditions, avoid any foods with high moisture content.
Water: Preventing Drowning
Firebrats need moisture to survive, but they are notoriously bad at avoiding open water — they will walk directly into a water dish and drown. To solve this, we use glass test tubes with a cotton ball plug. The firebrats can drink moisture from the cotton without any risk of drowning, and the glass tube doesn't raise the humidity inside the enclosure the way an open dish would.
This is a simple but critical setup detail. Never use open water dishes with firebrats.
Breeding: Building a Thriving Colony
When kept at the correct temperature (95–100°F), firebrats breed readily and consistently. Females lay eggs in warm, sheltered spots — which is why the cotton-stuffed toilet paper rolls are so effective as egg-laying sites. Eggs hatch in approximately 2–4 weeks depending on temperature, and nymphs look like miniature adults from the start.
To maximize breeding success:
- Keep temperatures consistently in the 95–100°F range
- Provide plenty of egg-laying sites (toilet paper rolls with cotton)
- Keep the enclosure dry — humidity is the enemy of a productive firebrat colony
- Feed regularly to ensure females have the nutrition needed for egg production
With the right setup, a firebrat colony can become self-sustaining within a few months, providing a continuous supply of feeder insects.
Quick-Reference Care Summary
- Species: Firebrat (Thermobia domestica)
- Enclosure: 27QT Sterilite container with latching lid (smooth interior)
- Substrate: Dry Turface
- Temperature: 95–100°F ground level
- Ventilation: Minimal — open 1–2x per week
- Food: Fish flakes, Feeder Chow, chick feed
- Water: Glass test tubes with cotton ball plugs — no open water
- Egg-laying sites: Toilet paper rolls stuffed with cotton balls
- Hides: Rolled cardboard cylinders
Final Thoughts
Firebrat care and breeding is surprisingly straightforward once you nail the temperature and housing requirements. They're a rewarding feeder insect to keep — prolific, easy to feed, and a great option for keepers of small reptiles, amphibians, and invertebrates. At Thrive Ecosystems, we're always happy to answer questions about our feeder insects and supplies.
Check out our Feeder Chow and Supplies section for everything you need to get your firebrat colony thriving.
**Disclosure: This post contains affiliate links. We may receive commissions for purchases made through links in this post, but these are all products we personally use and highly recommend.**