Armadillidium nasatum Isopods

If you have turned over stones in an old quarry in southern England, you may already have met this one. Armadillidium nasatum has been recorded outdoors there since at least 1900, on dry, open ground such as quarries, railway lines and coastal grassland, and further north it turns up in garden centres. This is the standard form of the species, and it carries that outdoor toughness indoors, which makes the wild-type an easy and very forgiving place to start.

In colour it stays understated: grey to brownish grey, often marked with paler stripes running the length of the body, and reaching a modest 12 to 16mm when fully grown. Look closely at the front of the head and you will find the feature that names the species, a small plate jutting forward between the antennae that reads rather like the peak of a cap. It conglobates like other pill woodlice, though never completely: the ball stays slightly open at the front with the antennae visible, where an A. vulgare would shut itself away entirely. The wild-type is also the parent stock behind the brighter selectively bred lines, so once you know its shape you can trace the very same body in the vivid Orange, the speckled Dalmatian and the ghostly White morphs.

Why begin here? Because very little goes wrong. It is exceptionally hardy, reliable to breed and unbothered by the small mistakes every new keeper makes, which is precisely what you want from a first colony. It also earns its keep as a cleanup crew, grazing leaf litter, spent food and animal waste in a bioactive setup, so it is as useful in a drier reptile enclosure as it is on a shelf of its own, though it may nibble soft live plants in a planted tank. As beginner Armadillidium go it has few rivals, and it sits comfortably within the wider Armadillidium collection alongside other forgiving favourites such as the Magic Potion line.

Care is refreshingly undemanding. Keep it at 18 to 24°C: an English home averages about 19°C over the heating season, so a heated room covers most of the year, and if you want young through the winter, add a low-wattage heat mat or heat cable on a thermostat, fixed to the side of the tub and never underneath. Aim for moderate humidity in the region of 50 to 70%, but arrange it as a gradient with one reliably damp end and one distinctly drier end, because in the wild this species lives on dry, sunny ground and shelters in damper spots under stones. Offer medium to high ventilation to keep the air fresh and stale pockets from forming. Over a moisture-retentive base, a layer of flake soil works nicely, then pile on plenty of leaf litter and a few pieces of cork bark for cover and grazing, and always keep a calcium source such as cuttlefish bone within reach for clean, trouble-free moults. Feed the usual detritivore fare, with decaying wood and dried leaves permanently on offer and the occasional slice of carrot, squash or a light pinch of fish flake for protein; a handful of springtails living alongside them will quietly eat the soft mould and leftovers.

Breeding asks nothing of you beyond patience. Give a settled group warmth, steady moisture and enough calcium and it will breed readily, the females carrying their eggs and then their young in a brood pouch before releasing tiny versions of the adults, still short of their last pair of legs. Allow most of a year for a small starter culture to become a working colony, and the patience is repaid: this is an ideal first Armadillidium and a dependable engine for a bioactive tank. Our Armadillidium nasatum care guide goes deeper, from the nose plate to the Orange, Dalmatian and White lines.

Every culture is captive-bred here in the UK and packed to travel well: a ventilated tub of damp sphagnum moss, cushioned inside a double-walled box. We post Monday to Thursday by Royal Mail, on Next Day or Tracked 24, whichever you pick at checkout, and each order carries our live-arrival guarantee along with a 20% overcount as standard, so you can count on receiving a few more than you ordered.