Ember Bee Isopod Care Guide | Ardentiella sp. UK (2026)

Quick answer: Ember Bee isopods (Ardentiella sp. 'Ember Bee', formerly sold as Merulanella) are large Vietnamese isopods, around 20mm as adults, streaked in yellow, orange and red over a black underside. Keep them at normal UK room temperature, roughly 19 to 26°C, with humidity in the 60s to low 70s held as a gradient over damp but never soaked substrate. Published figures go as high as 90%, so treat any single number with suspicion. Use a tall enclosure, cross-ventilated through two opposite walls, with a lid that seals everywhere except the vents, because they climb glass from birth. They do not need a heat mat. Stagnant damp air is what kills them.

Ember Bees are what I point people at when they want an Ardentiella but have only kept beginner species. They are the most forgiving animal in the genus, which is not the same as being a beginner isopod, and I have yet to see a care sheet that calls them one. Where the published advice contradicts itself, and it does, I have said so.

What an Ember Bee actually looks like

Jet-black legs and underside give way to a body streaked in yellow, orange and red, and a group crossing leaf litter really does read as bees rising out of hot embers. Patterning varies between individuals. Adults reach around 20mm, which puts them among the largest animals in the genus, and keepers running several morphs report them bigger than Red Diablo or Tri Colour. Most published figures fall between 19mm and 23mm, so treat 20mm as a working number rather than a specification.

The behaviour sets them apart. Most isopods are nocturnal, out of sight until dark. Ember Bees are active day and night, gather in loose groups on the surface, and live on bark rather than buried in substrate. They are not a burrowing species. As members of the family Armadillidae they are capable of rolling into a ball, though I rarely see mine bother.

The name, and what the 2025 revision really said

You will find this animal listed as both Ardentiella sp. 'Ember Bee' and Merulanella sp. 'Ember Bee'. Same isopod, and the second is the older name. In March 2025, B. Kästle and O.R. Regalado Fernández published a reassessment of Merulanella in the journal Natural History Collections and Museomics. It broke the genus apart: Merulanella was restricted to three New Caledonian species, and new genera were erected for the rest, one of which is Ardentiella.

Here is the part most listings leave out. Ardentiella was erected for two species from Myanmar, Ardentiella bicolorata and Ardentiella caerulea. The paper did not examine the Vietnamese animals that make up the pet trade, so moving Ember Bee, Red Diablo and the other hobby morphs across is the hobby's own inference from that work. It is a reasonable reading and we follow it. But nobody has formally described Ember Bee, and there is no type specimen or published locality. That is why an honest listing writes it as Ardentiella sp. 'Ember Bee', with the 'sp.' doing the work. Our guide to the genus covers how the morphs relate.

One further point from that paper is worth repeating. The authors note that some species in this group are considered endangered because of pet trade collection pressure, and that those species are not on the IUCN Red List. That is an argument for captive-bred stock, and a better one for keeping it alive. Wild-caught animals in this genus are markedly harder work. Ours are captive-bred; ask, if you buy elsewhere.

Build the enclosure before you order the animals

Two vents, facing each other

Everything that makes Ardentiella difficult lives in the enclosure rather than the food bowl. Ember Bee gives you more margin, not a different care sheet. What they want is humid air that keeps moving, which is awkward, since almost anything that raises humidity will also choke the airflow. Cross-ventilation solves it. Set fine mesh into one wall and more into the wall opposite, so a current crosses the box rather than pooling behind a single vent. Warm, wet, still air is the documented failure mode for the genus, and it is what empties a container that looked fine on Monday. Use more ventilation than you would for a Cubaris, not less.

Where they get out

They walk up vertical glass and polished plastic without difficulty, and the young do it as readily as adults. A manca will use a gap you cannot see, so go over the clips, the seams, the vent edges and the rim, and treat anything unsealed as an exit. Because they climb rather than dig, height serves them better than floor space. Stand cork bark on edge and give them branching routes upward.

Temperature and humidity, and why the figures disagree

Our range is 19 to 26°C, with the low twenties safest. Other listings give 22 to 26°C, a few go to 28°C, and one specialist keeper runs the whole genus at around 20°C. What nobody disputes is the direction of the risk: heat is what kills these animals, not cold. Several independent suppliers describe summer warmth as something colonies die from rather than merely dislike. I treat the mid twenties as the ceiling. If your house bakes in July, sort that out before ordering. Our temperature guide has the wider picture.

They do not need supplemental heat in a UK home. We used to recommend a thermostat-controlled heat mat for this species on our own listing, and I have changed my mind. A normal British living room sits inside the tolerated band for most of the year, and the exception is a hot spell, which is an argument for cooling rather than heating. A mat also dries the substrate and builds a hot spot in an animal that cannot dig away from it. A stable room, out of the sun and away from radiators, does the job.

Published humidity figures for Ember Bee run from 60% to 90%, which tells you how much precision is on offer. We aim for the 60s to low 70s, sloped so one end stays damper than the other and the animals can choose. The reading matters less than what it sits inside: substrate damp but never soaked, plenty of moisture-holding moss and litter, and real airflow over the top. Past 80% you are relying on heavy moss and heavy ventilation to stop the air going stale, which is not a balance I would ask a first colony to hold. The humidity guide covers the mechanics.

Substrate, leaf litter and calcium

Five to eight centimetres of living substrate suits them, based on organic topsoil and sphagnum with white-rotted hardwood and leaf mould mixed in. Coco coir alone is not enough: it holds water and offers nothing to an animal that eats what it walks on. Our substrate guide sets out a mix that works. Depth matters less than for a burrowing species, because these animals live on bark rather than under soil. Spend the effort on vertical furniture and the mix instead.

Top that with hardwood leaf litter, choosing species that break down slowly, and add white rotten wood, which along with the litter is most of what they actually eat. Keep a calcium source in permanently, whether cuttlebone, crushed oyster shell or limestone: a 20mm isopod moults hard and gets through it faster than you expect. I also run a springtail culture in there from day one. The species does not require it, but in a humid box springtails stay ahead of mould better than spot cleaning does.

Feeding and breeding

Leaf litter and decaying white wood form the base, topped up as it disappears rather than fed on a schedule. On top of that, offer soft vegetables in small amounts, a little animal protein in the form of dried shrimp or fish flake, and botanicals such as moss and lichen. Take out anything they have not cleared in a day or so: in an enclosure this humid, spare vegetable becomes a mould problem quickly and a mite problem shortly after. Underfeeding a colony with a deep litter layer is almost impossible. Overfeeding is easy.

Sources disagree on how prolific Ember Bees are, from fast to distinctly slow, and mine build steadily rather than explode. What they want is stability and to be left alone: hold temperature, humidity and airflow steady, keep food and calcium available, and resist digging to check. Young emerge as tiny mancae, still a pair of legs short of the adult count, and take some weeks to colour up. If a colony is not producing, I would look at ventilation, temperature and moisture before I looked at the food, and our breeding troubleshooting guide covers the usual suspects.

Frequently asked questions

Are Ember Bee isopods good for beginners?

No. They are the most forgiving animal in Ardentiella, which is a narrower claim than it sounds. They suit someone who has already run a hardier colony and understands ventilation.

Do Ember Bee isopods need a heat mat?

No. Normal UK room temperature suits them all year. They tolerate roughly 19 to 26°C and lean to the cooler part of that band, so the risk in a British home is summer heat rather than winter cold. Heat mats dry substrate and create hot spots.

How big do Ember Bee isopods get?

Around 20mm as adults, with most published figures falling between 19mm and 23mm. That puts them among the largest animals in the genus.

Can Ember Bee isopods climb glass?

Yes, easily, and so can the young. Vertical glass and smooth plastic are no obstacle. Any enclosure needs a lid that seals everywhere except the vents.

What is the difference between an Ember Bee and a Red Ember Bee?

'Red Ember Bee' is a separate morph name used mainly in the United States for animals showing red and black with little or no yellow. The names are not applied consistently, so check photographs of the actual stock.

Are Ember Bee and Merulanella the same thing?

In trade terms, effectively yes: this animal was sold as Merulanella for years and both names still appear on listings. Strictly, no. The 2025 revision kept Merulanella for three New Caledonian species and erected Ardentiella as a new genus for two from Myanmar, and the hobby moved the Vietnamese morphs across on that basis.

Where to go from here

If the ventilation has not put you off, our Ember Bee colonies are captive-bred and the sensible entry point. Scarlet and Lava are the usual next step, and the rest of our Ardentiella range follows once one colony is running steadily. Our Red Diablo care guide is the fullest treatment we have written and applies across the group.