Porcellio scaber is the rough woodlouse, a thumbnail-sized isopod found under logs on six continents. In captivity it is the most forgiving, most widely available, and most morph-diverse beginner isopod you can buy. If you have never kept isopods before, start here.
Key Takeaways
- Porcellio scaber tolerates 62 to 82 °F and humidity swings that would stress most other isopods.
- They need a humidity gradient: one moist side and one dry side. Equal moisture throughout the enclosure causes die-offs.
- Calcium is critical at every life stage. Always have cuttlebone or crushed eggshell available.
- Color morphs (orange, dalmatian, calico, white) breed true and are widely available for $5 to $25 per group.
- A colony of 20 to 30 animals will self-sustain and grow within 6 to 8 weeks under basic care.
What Is Porcellio Scaber?
Porcellio scaber belongs to the family Porcellionidae and is commonly called the rough woodlouse or common rough woodlouse. The “rough” refers to the granular, tuberculated texture of its exoskeleton, which is easy to feel and visible under a magnifying glass. Adults reach 1.5 to 1.8 cm and come in natural gray-brown, but decades of captive breeding have produced a wide range of stable color morphs.
They are native to Europe but have naturalized across North America, Australia, and parts of Asia. If you’ve ever turned over a piece of rotting wood in a garden and found flat, armored bugs that scatter, many of them were P. scaber. In the wild they live in dense, overlapping colonies under bark, stones, and leaf litter.
Unlike the related Armadillidium vulgare (roly-poly), P. scaber does not roll into a ball when threatened. It runs. This makes it slightly less charming to children but easier to photograph, and it’s often more active in the open.
Featured Snippet: Porcellio Scaber Care in Brief
Porcellio scaber needs a 6-quart plastic tub with a ventilated lid, one moist side and one dry side, temperatures of 65 to 80 °F, a substrate of coconut coir mixed with leaf litter and crushed limestone, constant access to cuttlebone, and weekly feeding of vegetables and protein. They breed readily and suit complete beginners.
Is Porcellio Scaber Right for You?
P. scaber is the right choice if:
- You’ve never kept isopods and want to learn without expensive stakes.
- You’re setting up a bioactive enclosure and need a reliable cleanup crew.
- You want to try morph breeding without specialist-level conditions.
- You’re introducing a child or teenager to invertebrate keeping.
The only time P. scaber is not ideal is if you’re keeping very low-humidity reptiles (they prefer some moisture) or if you want a species that doesn’t reproduce prolifically. They breed fast. In a warm setup with good food, a colony of 25 can become 200 within a few months.
Wondering whether isopods make good pets in general? The are isopods good pets guide covers exactly that question.
Enclosure Setup
Tank Size
A 6-quart plastic storage bin works for a starter colony of 20 to 30 animals. A 10 to 16-quart bin is better if you plan to let the colony grow. Glass tanks work too but retain less humidity and are heavier to move for maintenance.
Drill or cut a ventilation panel into the lid covering about 30 to 40 percent of its surface. Cover with fine mesh hot-glued to the inside. P. scaber is a moderate climber, so a 1-inch petroleum jelly barrier around the upper walls stops escapees if you go lidless.
Substrate Depth
Aim for 2 to 3 inches minimum. P. scaber does burrow but is not as deep a burrower as Cubaris species. The substrate serves as their humidity reservoir, hiding zone, and food source.
A reliable mix:
- 60% coconut coir (plain, no added fertilizers)
- 20% organic topsoil or rotted leaf mulch
- 20% washed play sand (improves drainage on the dry side)
Work crushed limestone, oyster shell grit, or calcium carbonate powder through the full mix at a rate of about 1 tablespoon per quart of substrate. This buffers pH and provides background calcium.
The Humidity Gradient
This is the most important concept in P. scaber care, and the step most beginners skip.
Divide your enclosure into two zones:
- Moist side: substrate should feel like a wrung-out sponge. Mist this half every 2 to 3 days.
- Dry side: substrate should feel barely damp to the touch. Don’t mist this half.
In practice, place your water source (a damp sphagnum moss chunk or a small water dish with a mesh cover to prevent drowning) on the moist side. Place hides and food primarily on the dry side. Animals self-regulate, resting in whichever zone suits their current hydration needs.
Enclosures with uniform high moisture across the whole substrate lead to bacterial blooms and die-offs within 4 to 6 weeks. Uniform dryness causes molting failures. The gradient solves both.
Temperature
P. scaber tolerates 62 to 82 °F but breeds most productively between 70 and 78 °F. Room temperature is usually sufficient in most homes. A low-wattage heat mat on the side of the enclosure (not the bottom) can help in cold rooms during winter.
They can survive brief temperatures into the low 50s, especially if the colony is large and well-fed, but don’t rely on this as a regular condition.
Feeding Porcellio Scaber
P. scaber is a detritivore and will eat almost anything organic that is decaying or calcium-rich. Their diet in the wild is broad, which makes captive feeding simple. The main risk is not underfeeding but overfeeding protein, which causes ammonia spikes in the substrate.
Staple Foods (always present)
- Leaf litter: dried oak, magnolia, beech, or hornbeam leaves form the base of their diet. Keep a continuous layer on the substrate.
- Cork bark and cholla cactus: provides grazing surface and shelter simultaneously.
- Dried hardwood chunks: they eat the fungal hyphae colonizing decaying wood as much as the wood itself.
Protein Sources (2x per week, remove after 48 hours)
- Dried shrimp or gammarus (3 to 4 pieces per 25 animals)
- Plain cooked chicken or boiled egg (pea-sized amounts)
- Dried mealworm
- Fish flakes (a pinch, sprinkled directly on substrate)
Protein is important but easy to overdo. A small amount twice weekly is right for an established colony. Uneaten protein sitting in warm, moist conditions creates mold and bacterial problems quickly.
Calcium (always available, never remove)
- Cuttlebone: one piece per enclosure at all times. They graze it constantly.
- Crushed eggshell: sprinkle a tablespoon on the substrate every 2 weeks.
- Oyster shell grit: can replace eggshell.
Calcium deficiency shows up as dull, pitted exoskeletons and failed molts. Calcium excess is essentially impossible with these sources. Keep it available and don’t ration it.
Vegetables (1x per week)
Thin slices of zucchini, sweet potato, carrot, or cucumber. Remove within 48 hours. They’ll also eat mushrooms enthusiastically, especially dried shiitake or lion’s mane.
The isopod feeding guide covers the full rotation in more detail, including which foods to avoid and how to safely introduce protein to a new colony.
Molting
P. scaber molts in two stages, which surprises first-time keepers. The posterior half (back end) sheds first, then the animal waits a day or two and sheds the anterior (front) half. During this period the animal looks odd and seems to be in two pieces. This is completely normal.
Molting animals hide on the moist side of the enclosure. They eat the shed exoskeleton immediately after molting to reclaim the calcium. This is normal and beneficial. Do not remove shed exoskeletons.
A failed molt, where the old exoskeleton doesn’t come off cleanly, is almost always caused by insufficient calcium or humidity that’s too low on the moist side. If you find a stuck-molt animal, gently place it on a damp paper towel in a small container and mist lightly. It often resolves within a few hours.
Breeding Porcellio Scaber
P. scaber breeds readily without any special intervention. Females carry eggs in a brood pouch (marsupium) on their underside for 3 to 4 weeks, then release 10 to 50 mancae (juveniles). In optimal conditions a female can produce 4 to 6 broods per year.
At 72 to 78 °F with consistent food and calcium, a starter colony of 25 will begin visibly growing within 6 to 8 weeks.
Sexing
Males have pleopods (swimmerets) modified into copulatory structures visible on the underside with a magnifying glass. Females have a visible brood pouch when gravid. In practice, buying a group of 15 to 25 from a reputable source gives you a natural sex ratio and you don’t need to sex individuals.
Managing Population Growth
P. scaber reproduces fast. If your colony outgrows its enclosure, the easiest option is to move some individuals to a second tub or use excess animals as feeders for predatory invertebrates.
In a bioactive enclosure, the population will naturally stabilize around food availability and competition. More food equals more animals. The system self-regulates once you stop actively feeding.
For a detailed walkthrough of the first 30 days of a new colony, see how to start an isopod colony.
Color Morphs
P. scaber has more established color morphs than any other beginner isopod. All morph names are hobby-assigned, not scientific:
| Morph | Description | Availability |
|---|---|---|
| Standard | Gray-brown, wild-type | Everywhere, often free |
| Orange | Solid orange to peach | Common, $5 to $15 per group |
| Calico | Orange with dark mottling | Common, $10 to $20 per group |
| Dalmatian | Gray with white spots | Common, $10 to $20 per group |
| White | Pale cream to white | Common, $10 to $20 per group |
| Lottery | Mixed genetics, variable offspring | Common, $5 to $10 per group |
Morphs breed true under proper care. If you mix morphs, offspring will be a mix of both parents’ genetics. Most keepers keep morphs in separate colonies if they want to maintain a specific line.
Using P. Scaber in Bioactive Enclosures
P. scaber is one of the three standard bioactive cleanup crew species (alongside Armadillidium vulgare and springtails). They break down waste, eat mold, and aerate soil. Their tolerance for temperature and humidity variation makes them the most versatile option for mixed bioactives.
They’re suitable with most reptile and amphibian species that do not actively hunt them. Avoid pairing with very small species (neonatal geckos, tiny dart frogs) where size disparity creates risk. Also avoid species from very arid environments where the moisture needs of the isopods conflict with the enclosure conditions.
See the best isopod substrate gear review for substrate products that work well for both bioactive and dedicated isopod setups.
Frequently Asked Questions
Are Porcellio scaber good for beginners? Yes. They are the beginner isopod. They tolerate temperature variation, humidity fluctuation, and inconsistent feeding better than almost any other species. If you mess up the setup initially, they’ll usually survive long enough for you to correct it.
Do Porcellio scaber roll into a ball? No. Only Armadillidium species (pill bugs) roll into a ball as a defense. P. scaber runs when disturbed. You can pick them up easily, but they’ll walk across your hand quickly.
How big do Porcellio scaber get? Adults reach 1.5 to 1.8 cm (about 0.6 to 0.7 inches). Juveniles (mancae) start at around 1 to 2 mm and are barely visible to the naked eye.
How fast do Porcellio scaber breed? Quickly. A healthy female produces 10 to 50 mancae per brood and can have 4 to 6 broods per year. At room temperature, a colony of 25 can double in 6 to 8 weeks with good food and calcium.
What humidity do Porcellio scaber need? They need a gradient. Maintain 70 to 80 percent humidity on the moist half of the enclosure and 40 to 55 percent on the dry half. Equal high moisture across the whole enclosure is a common beginner mistake that leads to losses.
Can Porcellio scaber escape through small gaps? Yes. Juveniles are tiny enough to escape through mesh openings larger than 1 mm. Use fine-mesh ventilation panels or apply a petroleum jelly barrier along the top interior walls. Adults are easier to contain but will find gaps in poorly fitted lids.
Thinking about adding more isopod species? The complete isopod care guide covers the fundamentals, and the rubber ducky isopod care guide is the natural next step once you’ve established a P. scaber colony.