Porcellio baeticensis 'Violet' Isopods

Catch them at the right angle, with a beam of light falling across the enclosure, and Porcellio baeticensis 'Violet' earns its name. In flat, even lighting these Spanish isopods can read as plain slate grey, but shift your viewpoint and a soft purple-violet sheen washes over the back. I want to be straight from the start: it is a quiet, angle-dependent shimmer, not a saturated purple, and it deepens as the animals mature. The colour rewards patience and good light.

Known in the hobby as the Violet Baeticensis or Purple Porcellio, this is a medium-to-large member of the Porcellionidae, with adults reaching roughly 15 to 20 mm. They come from the Baetic mountain ranges of southern Spain, which tells you most of what you need about their care: warm, airy hillsides rather than humid rainforest floor. Colour intensity varies between individuals, so a settled group shows a range of stronger and softer sheens.

I keep mine on the drier side of moderate with a clear moisture gradient: most of the floor stays fairly dry while one corner, kept damp with sphagnum moss or a light mist, gives them somewhere to moult and drink. High ventilation matters more here than with tropical species, so a mesh lid or a generous run of holes earns its place. A substrate depth of 5 to 8 cm lets them burrow and holds humidity down low. Room temperature suits them, ideally 20 to 24°C, avoiding sustained spells above 26°C. Given their size, keep calcium constant: cuttlefish bone, crushed eggshell, oyster shell or limestone left permanently in the enclosure keeps moulting smooth. Like all Porcellio they cannot roll into a ball as an Armadillidium does, so rather than conglobating they rely on speed and cover when startled.

Feeding is undemanding. A base of dried leaf litter, oak, beech and hawthorn, alongside decaying hardwood and cork bark, does most of the work, topped up with vegetables every few days: carrot, courgette, butternut squash or sweet potato. A little protein once or twice a week, such as fish flakes or dried shrimp, keeps a breeding colony in good order. They eat more than dwarf species, but there is no need to overfeed, and I remove uneaten fresh food after a day or two to keep mould down.

The temperament is what keeps me coming back. Freshly arrived isopods hide while they weigh up the enclosure, which is normal settling-in, not poor health. Once they trust the place they grow bold and forage in the open, even in daylight. They can be a touch territorial, so a roomy setup of 15 to 20 litres or more, furnished with cork bark and leaf litter, keeps friction low and breeding steady. Females brood their young in a marsupium, then tend them for several weeks after birth, defending and helping them feed. That extended maternal care is unusual among isopods and a real pleasure to watch.

These are captive-bred and travel well, double-boxed and covered by a live-arrival guarantee on UK dispatch. To see how they sit against the rest of the genus, it is worth browsing the wider Porcellio collection.

Common questions

Is the violet colour really purple? It is subtle and angle-dependent. Under good light and once the animals mature you will see a soft purple-violet sheen, but in dim or flat lighting they can look grey-brown, so set your expectations towards understated rather than vivid.

Do they roll into a ball? No. Porcellio cannot fully conglobate, so they dash for cover rather than curling up.

Are they a good beginner isopod? They are hardy and adaptable, but their size, territorial streak and preference for a drier, well-ventilated setup make them a better second or third species than a first.

Give them space, airflow and plenty of calcium, and the Violet Baeticensis settles into an easygoing, characterful colony that quietly rewards a good light.