Cylisticus convexus Isopods for Sale UK

Cylisticus convexus stands out for its unusual rolling behaviour. It can curl into a flattened ball, but unlike many Armadillidium types the antennae and long pointed uropods usually remain visible, giving it a more angular, "curly" silhouette that many keepers find especially appealing in naturalistic setups.

Native across parts of Europe and Asia, with introduced populations elsewhere, this is a ground-active, cover-using species best kept in a fresh enclosure with leaf litter, bark, decaying wood, steady calcium access, and a clear moisture gradient. It is a better fit for buyers who enjoy realistic woodlouse behaviour than for anyone expecting constant open display.

What makes this species interesting

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  Rolling style: curls up differently from typical pill isopods, with visible antennae and pointed rear uropods.


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  Behaviour: usually nocturnal, detritus-led, and more active around litter, bark edges, and covered floor space than on bare substrate.


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  Enclosure use: best judged by where it settles and feeds under cover, not by daytime open-floor visibility alone.


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  Setup style: prefers a practical temperate-style enclosure with fresh air, a damp refuge, and a drier usable side rather than a wet tropical tub.

How they usually behave in the enclosure

Once settled, Cylisticus convexus often uses the upper substrate, leaf litter, bark undersides, and sheltered routes between the damper and drier parts of the enclosure. You may notice more movement in the evening or at night, and more quiet grazing under cover than obvious daytime roaming.

If they spend all their time crammed into one damp patch, that usually suggests the rest of the enclosure is too dry, too bare, or too stale to use comfortably. On the other hand, if they disappear after arrival or after frequent checking, that often means they are still settling rather than failing.

Before you order

Prepare an enclosure with a generous layer of leaf litter, pieces of cork bark or similar bark hides, some decaying wood, and one reliably damp refuge that does not turn the whole tub wet. The drier side should still have litter and cover so they can move without crossing exposed bare ground.

A little sphagnum moss can help hold moisture in the refuge area, but it works best as one damp pocket rather than spread across the whole enclosure. If you need a broader guide to balancing airflow, cover, and moisture, see the isopod habitat setup guide.

Feeding and calcium

This species should be fed as a detritivore first. The main diet should come from leaf litter, decomposing wood, and mature substrate, with fresh foods used only as occasional extras rather than the foundation of the colony.

Consistent calcium access is worth providing. Limestone is a simple option for long-term mineral access. If you want a wider overview of enclosure feeding, the guide on what do isopods eat is a useful next read.

Who tends to enjoy Cylisticus convexus

This species tends to suit keepers who like naturalistic, observation-led colonies and appreciate small behavioural details such as bark use, litter grazing, and that distinctive curled defensive posture. It also makes sense for buyers who want something different from a typical round pill isopod without moving into a tropical collector setup.

If your main goal is a more openly visible, food-responsive colony, Porcellio scaber Ghost is often the easier comparison. If you want a roller-type look with a more classic pillbug silhouette, an Armadillidium vulgare Albino comparison may also be useful.

Comparison and next step

Choose Cylisticus convexus if the appeal is the shape, the unusual curl, and a more natural litter-and-cover style of enclosure use. If you are still comparing options, you can browse all isopods or read the Ultimate Guide to Isopod Colonies for a clearer picture of how colony behaviour changes as numbers settle and grow.