Salmon isopods are Caribodillo martinicensis, a trade-name isopod that science has now caught up with. In November 2025 four researchers described the species, and a new genus to hold it, from animals collected on one hilltop in Martinique and from animals obtained through the pet trade, and found them identical in form. Hold them at 22 to 26°C in a tub with one end that never dries out, give them bark and stone to cling to, keep calcium on offer and add protein once a week. Females reach up to 15 mm and males 12 mm, they breed well, and in many of them, males especially, the tail section glows blue in the light of a 365 nm UV torch.
What a Salmon Isopod Is
The description, by Benedikt Kästle, Stephanie Binder, Nathan Jones and Mathieu Coulis, was published in the journal Zoosystema on 14 November 2025. They named the new genus Caribodillo for the Caribbean, with the -dillo ending common in its family, and we found no second species added since. The trade calls it Salmon or Martinique Salmon, and it has long been sold as Cubaris sp. 'Salmon', a label some sellers still use.
It is not a Cubaris. The authors separate it from true Cubaris by the lobes under its first two body segments, a flatter body and a longer tip to the tail plate, and point out that true Cubaris is thought to be Asian in origin. Its nearest relatives look to be Venezillo, which they describe as a genus of the American tropics and which also holds the tiny Venezillo parvus we keep. Its DNA barcode matched nothing closely in the public databases, which the authors put down mainly to how few land isopods from the American tropics have been sequenced, while reading it as support for the idea of an ancient Martinique endemic. They also suggest that some species from the American tropics still filed under Cubaris, such as C. flavobrunnea, may belong in Caribodillo, pending a look at the specimens.
Where It Lives in the Wild
Most hobby Cubaris come with no recorded wild locality, a gap we look at in Cubaris isopods in the wild. The Salmon has a hilltop, a date and a name. The type specimen, a male, was collected under a rock in dry forest on the summit of Morne Manioc, in Sainte-Anne in the south of Martinique, by Mathieu Coulis on 30 August 2016. The paper calls it the largest land isopod on the island, a species of dry, semi-deciduous forest that seems to prefer ridge tops where the soil is thin and limestone lies at the surface. Morne Manioc is its only known site, where it is particularly abundant, and the authors add that it could yet turn up on Dominica or St Lucia, whose isopods are little studied.
The hobby's animals trace back to the same hill. The authors report, from the original breeder, that the founders of the hobby cultures were collected at the type locality. They compared pet-trade animals from a German breeder with wild ones and found their form identical, took the DNA barcode from a pet-trade animal and included pet-trade specimens among the paratypes. They thank Jérémie Ruban, whose breeding of the species made the description possible, and say the trade does not appear to threaten it, because the animals on sale come from captive breeding rather than wild collection. Ours are captive-bred too.
Size and Colour
The paper gives a maximum body length of 12 mm for males and 15 mm for females, and those are the figures we go by. One European seller quotes 16 mm; where a seller and the describing paper differ, we use the paper.
The colour is described as uniform orange to brown, often with a grey head and antennae, matching the photographs on our listing: warm salmon-orange along the back, greyer at the front. One European seller says the older animals are the darker ones, and in the colony photographs on our listing the smaller animals are paler and greyer than the adults. One twist from the paper: a 2017 survey report mentioned red juveniles of this species, and when the authors examined them they turned out to belong to a different, smaller and bumpier species with a notch in its first body segment, so those red youngsters were not young Salmon at all.
The Blue Glow Under UV
Lit by a 365 nm torch, the tail section of live Salmon isopods fluoresced a strong blue. How much of it glowed varied from animal to animal, from the whole tail section to a central spot on its first two segments, and it covered notably more in males, while females showed only a little. The bristles showed up too, the largest brightest, especially on the legs and mouthparts. The authors saw the glow on living pet-trade animals and photographed it on specimens preserved the same day, because it fades quickly in alcohol.
They call it only the third documented case of UV fluorescence in land isopods, alongside the cave-dwelling Mesoniscus graniger and the St Helena endemic Pseudolaureola atlantica, and add that it is surely under-reported. Our Thai Blue Angel guide covers why isopods glow at all; the short version is that some isopods do, mostly pale ones, and the Salmon is a coloured animal with a published glow. Use a 365 nm torch, the wavelength in the paper, since a 395 nm torch, the cheaper and commoner kind, may show less. Keep looks brief and never shine UV into anyone's eyes. The glow described here is the paper's observation, not ours: when we have looked at our own colony under 365 nm, this paragraph will say what we saw.
Setting Up the Tub
Warmth comes first. Our panel says 22 to 26°C, and sellers range between 22 and 28°C. A UK living room stays below that for most of the year, summer included, so plan on gentle heat all year rather than just through winter: a heat mat or heat cable on a thermostat, against the side or back of the tub, never underneath. My own racks are warmed by heat cable rather than mats, because a mat often covers too much of a single tub.
Moisture is where sellers part company. One European seller keeps a third of the tub moist and the rest drier; an American seller keeps the whole tub evenly, lightly damp and warns that they do badly if it dries out. The wild habitat, dry forest on thin soil over limestone, leans towards the first, though the type specimen was found sheltering under a rock. We keep one end damp at all times and let the other end run drier but never dusty, with ventilation holes on opposite sides to keep air moving over the top. Our panel gives a humidity of 60 to 80 per cent. Aim for moist, never wet: squeezed substrate should hold together without dripping.
They are clingers. The paper describes them spending most of their time holding on to surfaces and rolling into a ball only when knocked loose, as seen in captive colonies, and that shapes the set-up. Surfaces matter more than depth: flat pieces of bark and a few chunks of limestone, which echoes the rock they live under and doubles as a calcium source. A substrate of 5 to 8 cm is plenty: organic topsoil, flake soil and crumbled white-rotted hardwood, under a layer of leaf litter. Coir holds moisture but has no food value for isopods that feed on their substrate, so it stays out of the base. To move them, lift the bark they are on rather than prising them off it.
Feeding
Food is the usual isopod menu: leaf litter as the staple, rotten hardwood and small amounts of vegetables, with calcium always available from cuttlebone, crushed shell or that limestone. Add protein once a week. One American seller calls them protein-hungry, and dried calciworms, the dried larvae of the black soldier fly, are rich in calcium as well. In a warm, damp tub, remove uneaten vegetables and protein after a day or two, and add tropical white springtails to clear the mould you miss.
Breeding
The paper puts the Salmon's spread through Europe and North America down to easy care and a high reproductive rate, and one American seller reports a fast-growing culture within three to four months at around 75 per cent humidity. Give a starter group steady warmth, the damp end and a little time, and it should build without further help.
Frequently Asked Questions
Are salmon isopods a type of Cubaris?
No. They were long sold as Cubaris sp. 'Salmon', but the 2025 description placed them in a new genus, Caribodillo, which the authors consider closest to Venezillo. The full name is Caribodillo martinicensis.
How big do salmon isopods get?
The describing paper gives maximum lengths of 12 mm for males and 15 mm for females. One seller quotes 16 mm; we use the paper's figures.
Do salmon isopods glow under UV light?
The describing paper reports a strong blue glow from the tail section under a 365 nm torch, varying between animals and covering more of the tail in males than in females. A 395 nm torch may show less.
Where do salmon isopods come from?
Martinique. The only known wild site is Morne Manioc in Sainte-Anne, in dry forest on limestone, and the authors report that the hobby cultures were founded from animals collected there. Ours are captive-bred.
Are salmon isopods good for beginners?
The describing paper credits easy care and a high reproductive rate for how widely they are kept. What matters most is steady warmth of 22 to 26°C and a damp corner that is never allowed to dry.
Do salmon isopods roll into a ball?
They can, but they are clingers first: the paper describes them holding on to surfaces and rolling up only when knocked loose. Expect to find them on bark and stone rather than balled up in the soil.
Where to Start
A starter group of Salmon isopods goes into a warm tub set up as above, with the bark and limestone in place before they arrive. Animals leave us in a double-walled box, bedded in damp sphagnum moss inside a ventilated tub, and every livestock order, whether it goes Tracked 24 or Next Day, carries our live arrival guarantee. Tell us within 6 hours of delivery if anything has not made it.
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