The Red Edge isopod is Cubaris sp. 'Red Edge', a rolling woodlouse sold by the trade as Thai, with no formal description that I have found. It has a grey to purple-brown back with an orange to red rim round every segment. My care panel gives 22 to 26°C and 75 to 85% humidity. Set it up with a deep living substrate under leaf litter and bark, a damp end and a drier one, air moving gently through, calcium always in, and a heat mat or heat cable on a thermostat, fixed to the side of the tub and never underneath, through the colder months at least. It comes in several colour lines, and other animals, a Porcellio among them, share the name. My Red Edge isopods are captive-bred.
What the Red Edge Isopod Is
'Red Edge', sometimes 'Red Skirt', is a trade name for a Cubaris sold in Britain, mainland Europe and America, mostly as Thai. I have found no formal description, type specimen or recorded collecting locality for it, so its scientific name stops at Cubaris sp. Even the genus is the trade's label: Cubaris, named by Brandt in 1833, holds more than a hundred described species and has become a wastebasket genus that researchers say needs revising.
What It Looks Like and How Big It Gets
Sellers who describe it agree on the rim, a band of orange to red along the edge of each segment. The body under it varies: they call it blue-grey, greyish-brown, purple or violet-black, and the two photographs on my listing show a marbled purple-brown animal with an amber rim and a paler, lilac-grey one with a tan-orange rim.
My care panel gives 18mm, a keeper's figure. Sellers' maximums run from about 15mm to 2cm. I have found no published measurement.
The Colour Lines
Besides the standard animal, I sell an Orange, a Peach and two pale listings. One US seller says its orange and white phases were mutations isolated from captive-bred Red Edge stock, and a Dutch seller calls its pale line a cultured morph. I have found nothing published on how any of these colours is inherited. Colour lines of one species will usually interbreed, and a cross can hide or muddy the colours of both, so keep each line in its own tub.
The Red Edge Orange is orange through the whole body, from pale apricot to deep amber in its listing's photos, rather than a dark animal with a coloured rim. The Red Edge Peach is my own name for a warm-toned line I hold, cream-yellow to golden with an orange-tinted head in its photos. I have found the name used nowhere else; its panel gives 16 to 19mm, measured on my own animals.
The pale animals are where the names tangle. I list a Red Edge Albino / Anderman's Pearl, and a Red Edge Blonde, both cream to off-white and both 15 to 18mm on their panels. A Dutch seller treats Blonde and White Phase as other names for Red Edge Albino and gives it red eyes; a British breeder has described its Blonde with black eyes; a US seller says most of its white phase have clear or pink eyes, though pink, yellow and beige ones with dark eyes have turned up. Whether Blonde and Pearl are one animal or two, I will not say, because the sources do not settle it.
Nor does eye colour. Researchers breeding nine woodlouse species recorded pale young in their cultures, and eyes of black, red, white or no pigment. In the woodlice that have been studied, body colour comes mainly from ommochrome pigments, not melanin, as my guide to which white isopod is which explains. 'Albino' is the trade's word and the name on my listing, but read it as hobby shorthand: I have found no breeding test behind it on any Cubaris. I have found the name Anderman's Pearl nowhere but my own listing.
Other Animals Sold as Red Edge
Sellers use 'Red Edge' for animals in at least three genera, so check the scientific name before you buy. My Porcellio echinatus 'Red Edge' is a selected line of a rough-backed Porcellio: flatter, quicker on its feet, and unable to roll into a ball. The 'Japanese Red Edge', which I list as the Miyako, is often sold as Cubaris iriomotensis, a name from the island of Iriomote in southern Japan, treated since Karasawa's 2012 paper as a synonym of the widespread Cubaris murina. It is smaller, 10 to 13mm on my Miyako panel, and I have found no study comparing it with the Red Edge sold as Thai. A Dutch seller also lists a pill woodlouse, Armadillidium xerovunense, as 'Red Edge'.
Setting Up the Tub
A plastic tub with a clip-on lid suits it. A starter group settles in a 3-litre tub, 4 to 10 litres gives more room, and a growing colony wants 6 to 9 litres; my own colonies live in 11-litre tubs, which hold a gradient more reliably, as my guide to how big a tub isopods need explains. Give it 5 to 8cm of organic topsoil, flake soil and crumbled white-rotted hardwood, which it eats as well as lives in. Coco coir holds moisture but gives a substrate-eater nothing to eat, so leave it out. Top it with a thick layer of dead hardwood leaves and plenty of flat bark for hides, and keep a pad of live sphagnum moss at the damp end.
Temperature and Humidity
My care panel gives 22 to 26°C for the Red Edge and its Orange, Peach and Blonde lines, and 22 to 27°C for Anderman's Pearl; sellers' ranges mostly start at about 24°C. An English home averages about 19°C over the heating season, below that band, and about 21.5°C in July and August, just under it, so this animal needs heat: a heat mat or heat cable on a thermostat, fixed to the side of the tub and never underneath, through the colder months at least. I run heat cable along the back of my racking.
My care panel gives 75 to 85% humidity for the Red Edge. The panels on its colour lines run between 60 and 85%, sellers' figures from 55 to 85%, and I have found no measurement behind any of them. The gradient matters more than the number: give the tub a damp end and a drier one. I keep one end wet enough that the sphagnum stays springy under a finger, mist it and let the rest dry back. Keep air moving gently through vents on two opposite sides: Cubaris want less airflow than some isopods, but never none. If the soil turns to mud or smells sour, it is too wet.
Feeding
It is a detritivore, so most of what it eats should be leaf litter and rotting wood: keep both always available. On top of that, give a little fresh food twice a week, such as a slice of courgette or squash, and protein once or twice a week, such as a pinch of fish flakes. Lift leftovers before they mould. Keep a calcium source in the tub at all times, a cuttlebone or a piece of limestone.
Breeding
Two US sellers report it very prolific, another ranks it among the more prolific Cubaris while giving it small to mid-sized broods, and a Dutch seller calls its albino line somewhat prolific once established. My own Blonde and Peach colonies have small broods, and a starter group here has not filled its tub by six months. I have found no published brood size, age at maturity or lifespan for it. The usual woodlouse pattern holds: both sexes are needed, the female carries her eggs in a fluid-filled pouch under her body, and the young leave it alive, pale and still short of their last pair of legs. Most woodlice live about two years, and some three or four; the common pill woodlouse, Armadillidium vulgare, can live up to about five.
I start colonies with twenty or more animals where I can; for a Cubaris like this, ten to fifteen is the floor. Keep conditions steady, give the females bark to shelter under, and then leave them to it.
Behaviour and Handling
Two sellers call it more active than most Cubaris, a Dutch seller says its pale line is mostly active at night, and a keeper found his newly arrived albinos super active. Startled, it rolls into a tight ball, as most Cubaris do. It cannot bite you and has no venom, so it is safe to pick up: let it walk onto a flat hand rather than pinching it up.
Is It a Good First Isopod?
It suits a keeper with a hardy species or two behind them. My care panels rate the Red Edge and its Orange and Peach lines medium and the two pale listings easy; sellers say hardy, easy to moderate or intermediate. For a very first isopod, start with a hardy Porcellio or Armadillidium, or with the Panda King or the Penguin, the easy end of the genus and fine even as a first isopod. My complete Cubaris care guide covers the genus as a whole.
Frequently Asked Questions
What is a Red Edge isopod?
Usually Cubaris sp. 'Red Edge', a rolling woodlouse sold by the trade as Thai, with a grey to purple-brown back and an orange to red rim round every segment. The name is also used for Porcellio echinatus 'Red Edge' and the 'Japanese Red Edge'.
How big do Red Edge isopods get?
About 18mm, the keeper's figure on my care panel; sellers give about 15mm to 2cm. The two pale listings are 15 to 18mm on my panels. I have found no published measurement for any of them.
Do Red Edge isopods need a heat mat?
Yes, through the colder months at least. My care panel gives 22 to 26°C, and an English home averages about 19°C over the heating season and about 18°C in December. Use a heat mat or heat cable on a thermostat, fixed to the side of the tub, never underneath.
Is Red Edge Blonde the same as Red Edge Albino?
The sources disagree, and I sell both without claiming either way. A Dutch seller uses Blonde as another name for Red Edge Albino and gives it red eyes, while a British breeder has described its Blonde with black eyes. Both are kept like the standard Red Edge.
Are Red Edge isopods good for beginners?
They make a good second or third species. My care panel rates the Red Edge medium and its two pale listings easy; they need steady heat, and my own colonies build slowly.
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