Porcellio scaber, the rough woodlouse, is probably the most commonly kept isopod in the UK hobby. It is also the one most of us have seen hundreds of times without thinking about it. Flip a plant pot, lift a brick, check under the shed, and there they are. Hardy, adaptable, and available in a growing range of colour morphs, P. scaber is the species most people start with, and plenty of experienced keepers still maintain colonies of it alongside more exotic species.
Quick facts
- Order: Isopoda, Suborder: Oniscidea
- Family: Porcellionidae
- Adult size: 10-18mm
- Lifespan: 2-3 years
- Origin: Europe (now distributed worldwide)
- Difficulty: beginner
Appearance
Wild-type P. scaber is grey-brown with a rough, tuberculated body surface (hence "rough woodlouse"). The body is dorsoventrally flattened and oval, with seven pairs of walking legs and a pair of short uropods at the rear. They cannot roll into a ball like Armadillidium species. When disturbed, they run.
The colour morphs available in the hobby are all the same animal underneath. Dalmatian (white with dark spots) is probably the most popular. Orange is a solid warm colour that breeds true. Calico is a patchy mix of orange, white, and dark. Lava is almost entirely dark, close to black. Each morph colony should be kept separate to prevent reversion to wild-type colouration through crossbreeding.
Enclosure
A ventilated plastic tub is all you need. A 9-litre Really Useful Box works well for a starter culture. Drill or melt a row of small holes along the top sides for ventilation. The lid needs to be secure, not because P. scaber are great escapers (they are not), but because an open tub dries out too fast.
As the colony grows, move up to something bigger. A 33-litre tub accommodates a large colony comfortably. Glass terrariums work too if you prefer something to look at rather than a stack of opaque boxes on a shelf.
Substrate
60% organic topsoil or coco coir, 20% sphagnum moss, 10% fine sand, and 10% crumbled leaf litter mixed through. Top with whole dried oak or beech leaves and pieces of cork bark. Depth of 5-8cm minimum. P. scaber is not picky about substrate as long as it holds moisture, drains reasonably, and contains no toxic chemicals. Avoid anything with added fertiliser or pesticide. No conifer products.
Humidity and temperature
P. scaber tolerates a wider humidity range than most isopod species, but it still needs a moisture gradient. Mist the damp side of the enclosure every couple of days and leave the other side dry. The substrate on the wet side should be moist but not waterlogged.
Temperature: 16-24C. This species does fine at normal UK room temperatures, even in an unheated room during mild winters. It slows down at lower temperatures and breeds more actively in the warmer part of the range, but it does not need supplemental heating under normal conditions. Avoid direct sunlight and heat lamps.
Diet
Leaf litter is the primary food. Oak and beech are standard. Top up leaves as they get consumed. On top of this, offer vegetable scraps once or twice a week: cucumber, carrot, courgette, sweet potato. A small amount of protein once a week (a pinch of dried shrimp, fish flakes, or dried mealworms) keeps the colony healthy and discourages cannibalism during moults.
Calcium must always be available. A piece of cuttlefish bone in the enclosure is the easiest approach. P. scaber will gnaw at it steadily. Replace it when it gets small.
Remove uneaten fresh food within 48 hours. Rotting vegetables attract grain mites and fruit flies, both of which are annoying rather than harmful but indicate you are overfeeding.
Breeding
P. scaber breeds readily. Females carry 20-40 mancae per brood in the marsupium and can produce several broods per year. At 20-22C, you can expect a new brood roughly every 6-8 weeks from each mature female. The mancae are tiny, pale, and stay hidden in the substrate for the first few weeks. Do not worry if you cannot see them. They are there.
A starter culture of 10-15 will typically start producing visible population growth within 2-3 months. By six months you should have a well-established colony. By a year, you will likely have more than you need and can start splitting cultures or selling surplus.
Common problems
Grain mites are the most frequent nuisance. Tiny white mites that appear on food and substrate surfaces, usually because of overfeeding or excess moisture. They are not harmful to the isopods but indicate something is off. Reduce feeding, remove affected food, improve ventilation, and let the substrate dry out slightly. They usually subside within a couple of weeks.
Colony die-offs in P. scaber are rare if the basics are right. When they happen, the cause is almost always environmental: substrate dried out completely, chemical contamination from a new product, or the enclosure was left somewhere too hot or too cold. This species is forgiving enough that partial losses often recover on their own once the problem is fixed.
Uses
P. scaber is popular both as a pet species (especially the colour morphs) and as a cleanup crew in bioactive terrariums. It breeds fast enough to maintain population in a bioactive setup even if the main animal eats some of them. For bioactive use, wild-type is perfectly fine. No need to sacrifice your Dalmatians as gecko snacks.
Why keep them?
Honestly, P. scaber is just a satisfying animal to keep. The colony grows, the morphs breed true, the maintenance is minimal, and there is always something happening under the bark when you lift it. It is the species that hooked most of us into this hobby in the first place.