A Glimpse
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Scientific Name: Ardentiella sp. "Lava" (formerly Merulanella sp.)
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Common Name: Lava Isopod
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Family: Armadillidae
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Origin: Vietnam
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Adult Size: 18–25 mm (this morph is reported to grow notably larger than other Ardentiella)
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Difficulty: Hard — captive bred specimens are more manageable, but this is not a beginner species
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Temperature: 19–26°C — cooler than you'd expect for a tropical species
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Humidity: 60–75%
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Ventilation: High — critical for this genus
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Diet: Leaf litter, white rotten wood, lichen, moss, vegetables, protein supplements
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Supplements: Cuttlebone, crushed limestone, or oyster shell for calcium
Please note: We also sell a completely different species called Porcellio scaber "Lava" — a beginner-level European isopod with a similar name but entirely different care requirements and price point. Make sure you're on the right page for the species you're after.
Lava Isopods: Overview
Lava Isopods are one of the most visually striking morphs in the Ardentiella genus — formerly classified under Merulanella before the genus was revised. The name says it all: deep reds, lava-oranges, and warm yellows contrasting against dark undersides, creating an appearance that genuinely evokes molten rock. Every individual shows slightly different patterning, so a colony has a living, varied look to it rather than each animal being an identical copy.
If you already keep other Ardentiella morphs — Batman, Ember Bee, Pink Lambo, Tricolor, or similar — you know exactly what to expect in terms of care. The genus shares the same fundamental requirements across all morphs. What sets the Lava morph apart, beyond its colouration, is size. Lava isopods are reported to grow noticeably larger than other Ardentiella in the hobby — up to around 1.5 times the size of something like an Ember Bee. Combined with the genus's characteristic boldness and activity level, this makes them one of the more impressive display isopods available.
Ardentiella as a genus are popular for good reason. They're active during the day as well as at night, they're noticeably bolder than most isopod genera, and they spend a lot of time out in the open rather than permanently hidden. You'll actually see these isopods moving around their enclosure, climbing on cork bark and branches, investigating food, and interacting with each other. For a lot of keepers, that visibility is what makes the genus worth the extra care it demands.
Why They're Rated Hard
The difficulty rating is honest, and it's worth understanding what it means before committing £80.
Two things kill Ardentiella colonies more than anything else: poor ventilation and frass buildup.
Ventilation: These isopods need high humidity AND excellent airflow at the same time. That's a combination that trips up a lot of keepers, because the natural instinct is to restrict ventilation to keep humidity up. With Ardentiella, stagnant humid air is lethal. You need cross-ventilation — mesh vents on opposite sides of the enclosure — so air moves through rather than sitting. This is the single most important thing to get right.
Frass buildup: Ardentiella are unusually sensitive to their own waste accumulating in the substrate. As frass builds up, it raises the acidity of the substrate, and colonies can crash surprisingly fast once this tips past a threshold. Replace the substrate every 6 months at minimum. If it starts looking dark, compacted, or spent before then, don't wait.
There is a significant caveat to the difficulty rating, though. Captive bred Ardentiella are dramatically easier than wild caught. The genus has a reputation for being fragile, but that reputation comes largely from people buying wild-collected animals from bulk importers, which often arrive stressed and fail to establish. CB populations that have been stabilised over several generations breed readily and are much more forgiving. If you're buying from us, you're getting CB stock, and that makes a meaningful difference.
Enclosure
The enclosure must be escape-proof. This is not a suggestion — it's a requirement. Ardentiella, especially mancae and small juveniles, can climb smooth vertical plastic like cockroaches. If there's a gap in the lid, they will find it and get out. Use a tight-fitting lid and inspect for openings.
These are semi-arboreal isopods. They'll use the substrate, but they also climb — on cork bark, branches, twigs, anything with texture. Provide a mix of horizontal hides and vertical climbing surfaces. Cork bark pieces (both flat and angled), lichen-covered twigs, and small branches all work well. The more three-dimensional the enclosure, the more natural behaviour you'll see.
Substrate
Use organic topsoil or forest humus (pesticide-free, fertiliser-free) mixed with crumbled white rotten hardwood and dried leaf litter. Keep it moist to the touch but not waterlogged — you shouldn't be able to squeeze water out of it. Top with a generous layer of whole leaves, moss, and pieces of soft rotting wood.
Substrate depth should be at least 8–10 cm. This gives the isopods a humidity gradient (damper at the bottom, drier at the surface) and space to moult safely.
Remember: the substrate is part of the diet. They eat it. Quality matters.
Temperature
This is one of the more surprising things about Ardentiella for people used to other tropical isopods. They prefer it cool — 19–26°C, with the lower end often being better. They can suffer in heat, and prolonged temperatures above 26°C can stress a colony. During UK summers, if your house gets warm, this is worth planning for. Some dedicated Ardentiella keepers use wine coolers or similar to keep colonies cool during heatwaves.
In winter, most UK houses will naturally sit within the ideal range without additional heating. If your room drops below 18°C regularly, a low-wattage heat mat on a thermostat can help — placed on the side of the enclosure, not underneath.
Diet
The primary diet is leaf litter and white rotten wood, which should always be available. Top up as it's consumed — if you can see substrate rather than a thick leaf litter layer, you need to add more.
Supplement with vegetables (courgette, sweet potato, carrot), occasional fruit, and moss and lichen, all of which are eaten and appreciated.
Protein is important for this genus — offer gammarus shrimp, fish flakes, or freeze-dried bloodworm once or twice a week. Calcium should always be available: cuttlebone left in the enclosure, or crushed limestone/oyster shell mixed into or placed on the substrate. Ardentiella consume noticeably more calcium than many other isopod genera, possibly related to their size.
Remove uneaten fresh food within a day. In a warm, humid enclosure, mould develops quickly and you don't want it establishing.
Breeding
Captive bred Ardentiella breed at a fair to prolific rate once established, but growth is slow. Don't expect rapid colony expansion — this is a genus where patience pays off. A starting group of 5 gives a reasonable chance of having both sexes represented, and from there it's a matter of maintaining conditions and letting the colony find its own pace.
No special triggers are needed for breeding — just consistent, correct husbandry. Good ventilation, clean substrate, varied diet, appropriate temperature. The colony will do the rest.
Being Realistic About the Price
At £80 for 5, this is the same price bracket as our Ardentiella Batman Isopods, and the same honest advice applies. If you haven't kept isopods before, don't start here. Begin with something forgiving — Dairy Cows, Powder Blues, or even an easier Cubaris species — and learn the fundamentals of humidity, ventilation, and substrate management on species that won't punish small mistakes with colony collapse.
If you've kept other isopods successfully and you're comfortable managing the ventilation-humidity balance, Ardentiella Lava are genuinely rewarding. The colours are spectacular, the size is impressive for the genus, and the active, bold behaviour means you get far more visual enjoyment than from species that spend most of their time hidden. Just respect the requirements — especially ventilation and substrate freshness — and they'll do well for you.
