Porcellio expansus 'Orange' Isopods

Porcellio expansus 'Orange', the Giant Spanish Isopod, is one of the largest woodlice you can keep, and this colour form wears a bright, traffic-cone orange you can pick out from across a room. Adults reach around 2.6 to 3.8 cm in body length, and the well-known La Sénia form can push past 5 cm from antennae to tail. Where the standard animal is a muted slate grey, the Orange morph blazes right across its broad back. Big and bright at the same time, it is a species you build a display around rather than a background cleanup crew.

This page is our general Porcellio expansus 'Orange'. If you are after a specific line, we also keep an Expansus 'Orange' Tortosa locality, bred from that one Spanish location. Both are the same species in the same orange, and the Tortosa page is simply the locality-specific stock for keepers who track where their animals come from. You will see this woodlouse sold under nicknames too, Dragon Isopod and Beetlejuice Isopod among them, but it is all Porcellio expansus underneath.

These are captive-bred livestock, though the wild animal tells you exactly how to keep them. Porcellio expansus is endemic to the rocky limestone hills of Catalonia and Aragon in northeast Spain, not France or Italy whatever some older articles claim. That Mediterranean home is the entire care brief. Give them a dry, airy enclosure rather than a humid one, with plenty of ventilation, the bulk of the substrate kept on the dry side, and just one damp corner they can visit to drink and moult. Overwetting or stagnant, stale air is the quickest way to lose a colony.

For substrate I build a free-draining base of flake soil, rotted hardwood and topsoil, kept mostly dry, and I avoid a plain coco-coir base because it holds far too much water. Expansus want a hardwood-based mix, so leave softwood out of it altogether. A depth of 5 to 10 cm lets them burrow and bury themselves through the day while the surface stays dry. Crushed limestone or cuttlebone worked through the substrate reflects their rocky origins and keeps calcium in front of them at all times, which a large, frequently moulting isopod leans on for every new shell.

Room to warm temperatures, roughly 18 to 26°C, keep them comfortable, and most heated homes already sit in that band without any extra help. Alongside leaf litter and rotting wood they are protein-hungry, so keep a protein source available, fish flake, dried shrimp or similar, rather than offering it only now and then. Stacked cork bark, flat rocks and plenty of hides give them the cover and surface they want to roam across. They are slow-growing and long-lived, three to five years is normal, so a colony builds steadily rather than quickly and rewards a patient keeper.

One thing worth knowing upfront: like all Porcellio, expansus cannot roll into a ball. It is flat-bodied and relies on size, speed and diving for cover instead, so if you want a pill-rolling isopod this is not the one. What you get in return is a large, active animal that forages out in the open and is a pleasure to watch. If the giant Spanish Porcellio pull you in, look also at the Titan (Porcellio hoffmannseggii), its Sevilla locality, and Porcellio magnificus, or browse the wider Porcellio collection.

Every order is captive-bred, boxed double-walled around a ventilated tub of damp sphagnum and posted Monday to Thursday by tracked next-day Royal Mail, with a live-arrival guarantee and a small overcount as standard.