Quick answer: Sunset isopods (Troglodillo sp. 'Sunset', sold for years as Cubaris sp. 'Sunset Queen') are an undescribed isopod reported from Thailand, 12 to 20mm and warm orange, with a yellow-to-orange face and, on many animals, a darker rear. Keep them at 22 to 26°C, which in a British house means a heat source on a thermostat for most of the year. Give them damp air rather than a wet tub, 75 to 85% at the damp end with a drier side to retreat to, a deep substrate they can eat with limestone worked through it, and a lid that lets the air move. Easy on our panel, a steady breeder, and a gentle way into the cave-type isopods. Ours are captive-bred here in the UK.
The Sunset is the animal I suggest when someone has kept a Porcellio or an Armadillidium for a year, likes the look of the premium cave species and does not want to start with the least forgiving of them. It carries the rounded face and the low, wide build of that group, it wants the same warmth and the same damp air, and it is a more forgiving animal than a Rubber Ducky. That is why our panel rates it Easy, and why it is the Troglodillo I suggest to a keeper who wants the colour of the premium group.
What a Sunset Actually Is
'Sunset' is a trade name for an undescribed isopod from Thailand, and the genus on the label has moved. For years it circulated as Cubaris sp. 'Sunset Queen', and you will still find it under that name. The hobby reattributed it to Troglodillo, and that is where most of the hobby now lists it, but nobody has published the decision: there is no scientific name beyond the genus, no type specimen and no collection locality. Thailand is what the trade reports, and no source I have read offers anything more precise.
Troglodillo itself is real and old. Jackson erected the genus in 1937, it sits in the family Armadillidae, and it is not a recent split from Cubaris, whatever the old trade name suggests. Only three species have ever been formally described, all of them cave animals from Thailand and China; the first of them, Troglodillo emarginatus, is known from a single cave in Lampang province in the north of Thailand and nowhere else. Whether the Sunset lives in a cave or in the leaf litter outside one, nobody has written down. It has the flat, low body of the genus, and it shares a shelf here with the other Troglodillo we keep: the Soil isopods, the Camouflage and the Vex. Our guide to the types of Cubaris explains why the hobby's Cubaris label covers animals that are not Cubaris at all.
The Colour, and Why No Two Look the Same
The name describes a gradient. On a classic animal the colour warms from a yellow or orange face into an orange body and deepens towards the rear, sometimes to a dark brown, so the shift from glow to shadow plays out along one small woodlouse. In practice the gradient varies more than the name suggests. Our own photographs show one animal in warm orange end to end, another in pale peach with an orange head, and a third in orange-yellow with two dark marks on the rear segments, and the orange carries its own hue from one animal to the next. The seams between the segments read as fine pale lines, the legs and antennae are nearly white, and the eyes are small and dark. Juveniles come through paler and plainer; the orange builds as they mature through their moults, so do not judge a young group by its colour yet.
The build matters as much as the colour. Where a Rubber Ducky is tall and rounded and rolls into a tight ball, a Troglodillo is broad and flattened with a limited roll, and it wedges into a crevice when it is bothered rather than balling up. Adults are quoted anywhere from 12 to 20mm depending on who is measuring, which is why our panel gives the whole span. The colour reads best against a dark substrate under gentle, indirect light.
Warm, Not Hot: Temperature in a British House
Our care panel gives 22 to 26°C, and the sources do not agree with each other about it. One American source gives 18 to 24°C and warns that heat kills it; a European source gives 24 to 28°C. The panel sits between the two, and it is where ours live. What the range is for is worth knowing, because "tropical" misleads people. The described Troglodillo are cave animals, and the nearest measured proxy for what that means is a 1967 survey of the Dark Cave at Batu Caves in Malaysia, a cave with terrestrial isopods in it, which recorded 23 to 25°C across the whole year while the forest outside reached 29 to 30°C most afternoons. Stable and saturated, not hot.
A British home does not get there on its own. Measured across 823 English houses, the heating-season average is 19.0°C, December sits at 18.1°C, and July and August reach about 21.5°C. So for most of the year a Sunset needs help, and the help has to be regulated. I run a heat cable along the back of my racking on a thermostat, which holds a row of tubs inside the 22 to 26 band; an unregulated mat is what cooks a colony. Heat into the range and no further. Nobody has measured what heat does to a Troglodillo, but a feeding trial on a temperate Porcellio found that raising it from 20 to 28°C roughly doubled its mortality. That trial is on a different animal in a different climate, so it sets a direction rather than a limit, and it is why the panel stops at 26. In a July heatwave the job reverses: heat off, coolest room, out of the sun. Our heating guide covers the equipment and the numbers behind it.
Damp Air, Not a Wet Tub
Overwatering is the common way to lose a cave species, and the Sunset is no exception. It wants humid air, and the mistake is to give it wet substrate instead: a waterlogged tub brings failed moults and sudden losses. Aim for substrate like a wrung-out sponge. Hold the damp end at around 75 to 85% with sphagnum and a light misting, and leave the far end drier under dry leaf litter so the animals can choose. The drier end has to be truly drier. The only woodlouse anyone has measured for this, a temperate Porcellio, shows no response to humidity at all unless part of its enclosure sits below about 65%, and a tub that reads 80% at one end and 85% at the other offers one condition with a label on it rather than a choice. One European source runs the Sunset drier than our panel, at 50 to 70%, and calls it adaptable. Our panel sits at 75 to 85 at the damp end because we pair it with a drier side that really is drier, and the animals choose. Mist to top up, never to soak.
Ventilation is the other half of the same question, because you cannot hold a drier end in a sealed box; the moisture equalises and the gradient disappears. My own tubs carry large vents, two to four on each, and an oscillating fan moves air across the racking through the day; the cave species get the gentler end of that, and they still get it. What they must not have is still, wet air. Our ventilation and humidity guide goes through the mechanics, and the mould guide explains what happens in a tub where the air stops moving.
Substrate, Limestone and Calcium
Build the substrate 6 to 10cm deep on organic topsoil, flake soil and white-rotted hardwood, a base the animals can burrow into and eat, rather than coco coir, which holds water and offers no food to an animal that eats its substrate. Work crushed limestone through the mix and leave a piece of limestone or cuttlebone in permanently. The described members of the genus are cave animals from limestone country, and whether or not the Sunset is one, a colony short of calcium fails moults and stops breeding, so I treat calcium as part of the habitat rather than a supplement. Our limestone guide covers what to buy and what to avoid, and the substrate guide has a working mix. Over the top goes a generous layer of hardwood leaf litter, and magnolia lasts especially well, with cork bark, flat stones and crevices for cover. Plenty of hiding places are what make a Sunset feel secure enough to feed and breed; short of cover it goes under and stays there.
Feeding
Leaf litter and rotting white wood are the diet and should never run out; top them up as they vanish rather than to a timetable. On top of that base I offer soft vegetable once or twice a week, sweet potato, courgette or squash in small pieces, and a little protein a couple of times a week, fish flake, dried shrimp or an isopod blend, which supports breeding and takes the edge off any nibbling at moulting animals. Keep calcium freely on offer. I feed a wide variety across the whole range of foods we sell, because a varied diet is the thing I have found does most for breeding. Go easy on portions and lift anything uneaten within a day or two; at this humidity leftovers turn to mould fast. A springtail culture seeded from day one stays ahead of the mould and cleans up after the protein, and in a tub this humid it is cheap insurance.
Breeding, Steady Rather Than Quick
Breeding is steady. Descriptions elsewhere run from moderate to prolific, and I suspect the difference is temperature and how long the group has been left alone. Females carry their eggs in a brood pouch and release live young, the mancae come through pale and take on the orange as they mature, and a settled group given warmth, calcium and cover builds into a self-sustaining colony over time. The early settling period can feel quiet. The most useful thing you can do in it is nothing: hold the temperature, keep the damp end damp and the calcium constant, and resist the urge to dig through the tub to see how it is going.
Start with a group. I start my own colonies at twenty or more animals where I can, because a bigger group settles faster and gives a better spread of colour; with a species in this tier the budget usually decides, and ten to fifteen is the realistic floor. Our guide to how many isopods to start with sets out the arithmetic. Give a new group a few months before you expect anything, and a year before you expect to split it.
Is the Sunset the Right Isopod for You?
It is rated Easy on our panel, and I stand by that with one caveat: easy for a cave species. It still wants the thermostat, the gradient and the moving air, and a week in a cold room or an afternoon in the sun will still cost you animals. What it does not do is punish the small errors the way the Vex or the Camouflage do, and it breeds while you learn. If you have never kept an isopod, start with a Porcellio or an Armadillidium and come back. If you have kept one of those through a year and want the rounded face and the warm colour of the premium group without the difficulty that usually comes with it, this is the one. Our complete Cubaris care guide is the place to learn what all the cave-type species want, and the Soil isopod guide covers the Sunset's beginner-friendly genus-mate.
It suits the keeper who wants a display colony in warm colour, and the collector building a shelf of Thai species. It is not a cleanup crew, it is more secretive than a Porcellio, and you will see most of it in the evening. Give it its own tub: two flat orange Troglodillo in one box is a sorting job you will never finish, and our guide to keeping different isopods together covers when mixing works and when it does not.
Frequently Asked Questions
Is the Sunset isopod a Cubaris?
No, though it was sold as one for years and you will still see the old name. It is an undescribed Troglodillo, a genus in the family Armadillidae named in 1937, placed there by the hobby rather than by a published description. The care is close to a premium Cubaris, which is why the confusion never mattered much in practice.
How big do Sunset isopods get?
Between 12 and 20mm as adults. Sources quote 12mm at one end and 20mm at the other, so the panel gives the whole span rather than picking a number.
Do Sunset isopods need a heat mat?
For most of the British year, yes, and always on a thermostat. An English home measures about 19°C in the heating season and 21.5°C in July and August, and the ideal band starts at 22. A side-mounted mat or a heat cable on a thermostat holds the tub inside the 22 to 26 band.
What humidity do Sunset isopods need?
Damp air at one end, 75 to 85% on our panel, and a drier end they can move to. Some keepers run them drier still and report no trouble. The number matters less than the gradient and the ventilation that keeps it.
How fast do Sunset isopods breed?
Steadily. Expect a quiet first few months, then a trickle of mancae that builds through the year once the tub has been held stable. Faster than a Vex, slower than a Dairy Cow.
How long do Sunset isopods live?
No published figure exists for this animal. Our complete Cubaris guide puts the cave-type group at two to three years in good conditions, and I would plan on that.
Why was it called the Sunset Queen?
The 'Queen' came with the old Cubaris label, which the hobby's taxonomy trackers no longer accept. 'Sunset' describes the gradient from a yellow-orange face to a darker rear. Hobby names describe the animal; they are not taxonomy, and there is no more official name to give you.
Where to Start
The Sunset listing carries current stock, and our Troglodillo collection has the Soil, Camouflage and Vex beside it. Every colony we send is captive-bred here in the UK, travels in a ventilated deli tub on damp sphagnum inside a double-walled box, is dispatched Monday to Thursday so nothing sits in the post over a weekend, and comes with our live arrival guarantee and a 20% overcount.
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