If you are just getting into isopods, the sheer number of species available in the UK hobby right now can be a bit overwhelming. Prices range from a couple of quid to well over fifty pounds per individual. Some species breed like mad in a plastic tub on a shelf. Others need very specific conditions and will quietly die off if anything is slightly wrong. Here are the species I would actually recommend starting with, and why.
Porcellio scaber (rough woodlouse)
This is the one you have probably already seen in your garden. P. scaber is native to the UK, absurdly tough, and breeds readily in captivity. It tolerates a wider range of humidity and temperature than most species in the hobby. If you can keep the substrate from drying out completely and provide some leaf litter, you will have a colony.
The wild type is a grey-brown colour, but there are several morphs available in the hobby: Dalmatian (white with dark spots), orange, calico, and others. These morphs are just as easy to keep as the wild type. A culture of 10-15 will establish itself within a few months, and you will have more than you know what to do with inside a year.
Armadillidium vulgare (common pill bug)
The other classic UK starter. A. vulgare is the one that rolls into a ball when disturbed, which makes it immediately endearing and also very easy to handle. It is hardy and tolerates drier conditions than most isopods, though you should still maintain a moisture gradient in the enclosure. It is not as fast to breed as P. scaber, but colonies build up steadily.
Several colour morphs exist, including the popular "Magic Potion" (orange and grey patterning) and various solid-colour lines. These tend to cost a bit more than wild-type but the care is identical.
Porcellio laevis (smooth woodlouse)
P. laevis is larger than P. scaber, faster-moving, and breeds quickly. The "Dairy Cow" morph (white with dark blotching) is particularly popular. This species is a good choice if you want a colony that grows fast, but be aware that it is more protein-hungry than the previous two. If you do not provide enough protein, P. laevis will cannibalise weaker individuals. A small amount of dried shrimp or fish flakes once a week prevents this.
They are also a bit bolder and more active than Armadillidium species, which makes the enclosure more interesting to watch. On the flip side, they are fast runners and will scatter when you open the lid, so handling is less straightforward.
Oniscus asellus (common shiny woodlouse)
Another UK native that does well in captivity. O. asellus is glossy, flat-bodied, and prefers things a bit damper than P. scaber. It is a solid starter species that gets overlooked because it is not as colourful as some of the others. But it is forgiving, breeds well, and is cheap to buy if you cannot just collect a few from under a log in the garden.
Armadillidium nasatum (nosy woodlouse)
Named for the small pointed projection on its head (the "nose"), A. nasatum is a hardy species that does well at room temperature. It can conglobate like A. vulgare and is similarly easy to care for. Colony growth is moderate. It is not as widely available as some of the others on this list, but specialist shops and online sellers carry it.
Species I would not start with
Anything in the genus Cubaris is not a beginner species, whatever their appeal. Rubber Ducky isopods (Cubaris sp.) look incredible and command high prices, but they need stable high humidity (75-90%), consistent warmth (22-26C), and good ventilation, all at the same time. Getting that balance right is harder than it sounds, and at the prices these go for, mistakes are expensive.
Armadillidium maculatum (the Zebra isopod) is a step up from the species listed above. It needs higher humidity than A. vulgare and colonies take longer to establish. Not impossible for a beginner, but you will learn more and lose less money starting with something hardier.
Spanish and Portuguese Porcellio species (like P. hoffmannseggii and P. expansus) tend to need warmer, drier conditions than the UK species and are less forgiving of mistakes with humidity.
How many to start with
Buy at least 10, ideally 15 or more. A tiny starter culture of 5 is vulnerable. One dies, another turns out to be the wrong sex ratio, and suddenly you are down to 3 individuals that may or may not breed. More individuals means more genetic diversity and a better chance of a healthy, breeding colony from the start.
The setup is the same for all of them
All of the beginner species above do well with the same basic setup: a ventilated plastic tub, 5-8cm of substrate (organic topsoil and coco coir mix with sphagnum moss), a layer of dried oak or beech leaves, some cork bark for hides, a piece of cuttlefish bone for calcium, and a moisture gradient. Feed weekly with veg scraps and a touch of protein. That is genuinely all there is to it for these species.
Get one colony established and running well before buying a second species. It is tempting to start five cultures at once, but you learn much more by focusing on one and actually observing what the isopods do. How quickly they eat the leaves, where they congregate, how fast the population grows. That experience transfers directly when you move on to trickier species later.