Lava Isopods (Ardentiella sp.)

Let me be straight before this goes in the basket: the Lava Ardentiella is a rare, striking, genuinely difficult isopod, and it is not the one to learn on. In return for careful keeping it gives you some of the most dramatic colour in the hobby, deep reds, lava-oranges and warm yellows over dark undersides, on one of the largest bodies in its genus. If you have kept Ardentiella before you know the drill; if you have not, I would honestly rather you started elsewhere and worked up to it. Our stock is captive-bred here in the UK, which matters more with this genus than most.

Introduction

This is Ardentiella sp. 'Lava', a Vietnamese hobby morph. You will still see it sold as 'Merulanella' on older sites: the whole trade group was moved into the new genus Ardentiella in a March 2025 revision, so the husbandry advice under either name still applies, but Ardentiella is the current term. The care is shared right across the genus, so if you keep Scarlet, Batman or the others in the collection, Lava asks nothing new of you. What sets it apart is the molten colouring and the size.

Appearance

Lava is among the larger morphs in the genus at roughly 18 to 20 mm, reportedly up to around one-and-a-half times the bulk of an Ember Bee. The body is relatively flat, built for climbing and surface activity rather than deep burrowing, and every animal is patterned a little differently, so a colony has a varied, living look rather than a row of identical copies. The warm colours firm up as mancae mature.

Care

Two things catch keepers out, and both run against instinct. First, ventilation: Ardentiella want high humidity and high airflow at the same time. Cross-ventilate through fine mesh on opposing sides so the air moves through the enclosure rather than sitting in it; stagnant humid air kills them faster than almost anything. Second, temperature: these are cool-preferring at 19 to 26°C, happiest at the lower end, and they suffer above 26°C, which makes UK homes a good fit for most of the year but a summer heatwave a real risk worth planning cooling for. Keep humidity moderate at 60 to 75% on a gradient, never soaked, and note they climb smooth plastic and glass like cockroaches, mancae included, so a genuinely escape-proof, tight-lidded setup is non-negotiable. Give vertical structure, cork bark and branches, for the surface behaviour, plus constant calcium from our calcium range.

Substrate and the frass trap

The other common failure is the substrate itself. Ardentiella are sensitive to frass build-up, which raises acidity and has crashed colonies within weeks once it tips over. Work on quality organic topsoil or forest humus with white-rotted wood and hardwood leaf litter through and over it, keep springtails in there to hold down mould, and, the non-negotiable part, replace the substrate every six months. Some keepers go every four; few successful ones stretch past six. If a colony is going to fail, this and the ventilation are usually why. Our guide to why colonies crash is worth a read first.

Diet and breeding

Hardwood leaf litter and white rotten wood are the foundation, constantly grazed; add lichen and moss where you can, fresh vegetable such as courgette or sweet potato, occasional fruit, protein once or twice a week and a permanent calcium source. One quirk: bee pollen, a hit with many isopods, is largely ignored here, so do not waste it. Established captive-bred colonies breed at a fair to prolific rate, but slowly, with mancae released fully formed and colouring up over successive moults. Growth is genuinely slow across all stages, so a starter group can take a year or more to show real recruitment. Patience is part of the husbandry.

Who is this for?

The Lava Ardentiella suits the experienced keeper with success across several genera, the display enthusiast after dramatic warm colour, and anyone whose home runs cool enough to spare it the summer heat. It is not for beginners, for setups that cannot deliver high ventilation, or for homes that regularly pass 26°C without cooling. Bought with eyes open, it is one of the most rewarding animals in the genus.

All stock is captive-bred here in the UK and travels under our live arrival guarantee, in a ventilated deli tub with damp sphagnum inside a double-walled box. We post Monday to Thursday by Royal Mail next day before 1pm, with a 20% overcount in every order.