The Cherry Blossom is one of the few isopods that people buy on a photograph and then find the photograph was accurate. Soft pastel pink broken by pale cream segmentation, and against dark substrate it looks like exactly what it is named after. It is also expensive, slow, and less forgiving than almost anything else you might have kept, so it is worth understanding what you are taking on.
This guide covers what the animal actually is, the one part of its care that trips people up, and what "slow" means in practice when you are waiting for a colony to do something.
What it is, and why that matters
Cherry Blossom is Cubaris sp. "Cherry Blossom", and it is not a wild-collected species. It is a selectively bred colour line, isolated in Japan from Cubaris sp. "Red Pak Chong" stock. Two independent suppliers describe it the same way, and it is also sold under the name Sakura.
That makes it a sister line to the standard Red Pak Chong rather than a separate animal, and it has two consequences worth knowing.
The first is practical. A selected colour line is a population that somebody kept choosing from, generation after generation, for one trait. It breeds true enough to sell under the name, but it carries the care requirements of its parent stock, so Red Pak Chong husbandry is the right starting point rather than anything exotic.
The second is about sourcing. Because the line was established in captivity, buying one is not drawing on a wild population. That is a real distinction in a genus where a great deal of the trade still rests on collection from Southeast Asian limestone cave systems. Our wider piece on why isopods are so expensive covers what actually sets the price on animals like this.
Appearance, and what to expect from a group
Adults reach around 15mm. The body is pastel pink with paler cream banding at the segment edges, and the effect is at its best under a decent light against a dark background, which is worth setting up deliberately rather than hoping for.
They conglobate, rolling into a ball when disturbed, like the rest of the genus. What sets them apart from most premium Cubaris is that they are reasonably surface-active. They are quiet rather than shy, and a settled colony will be visible in the evenings and after a misting rather than permanently underground. For a species at this price, being able to see them matters more than it sounds.
Because this is a selected line rather than a fixed species, expect some variation in intensity across a group. That is normal in colour morphs, and our guide to isopod genetics, colours and morphs explains why.
The part that catches people out: airflow against humidity
This is the one thing to get right, and it is a genuine tension rather than a simple instruction.
Cherry Blossoms are a cave-type Cubaris. They want high humidity, around 70 to 80 per cent, and they want considerably less airflow than a Mediterranean Porcellio or Armadillidium, which are happiest with a proper cross-breeze. So the instinct is to close the box down.
Low is not none. Seal a tub completely and the air stops turning over entirely, and in a warm humid container with food in it that is how you get mould, stagnation and a colony that quietly stops thriving. What you are aiming for is low to moderate ventilation, enough that the air changes slowly, not enough to dry the substrate out. Our guide to enclosure ventilation and humidity works through how to set that balance, and mould in an isopod enclosure covers what to do when you have got it wrong.
The practical version: keep the substrate damp through its depth with a drier surface, clear uneaten fresh food promptly rather than letting it sit, and run a springtail culture alongside them, which handles surface mould without you doing anything.
Temperature, and holding it steady in a British house
Aim for 22 to 25°C. That is above what most UK homes sit at, so this is not a species you can keep on ambient alone, and stability matters here more than the exact number.
Fluctuation is what does the damage. A colony that swings between 18°C overnight and 24°C in the afternoon is under constant low-level stress, and the hardier species tolerate that in a way this one does not. A low-wattage mat on a thermostat, fixed to the side of the enclosure rather than underneath, gives you a warm end and a stable one. Side-mounting matters because these are burrowers, and a mat under the tub heats the layer they retreat into.
Summer is the other half of the problem and it gets less attention. A tub on a windowsill or in a conservatory during a British heatwave will go well past 25°C, and there is no thermostat setting that fixes a room. Pick where the enclosure lives with July in mind, not just January.
Substrate and calcium
Build the substrate deep enough for them to burrow into, on a nutritious base: flake soil, white-rotted hardwood and untreated organic topsoil. Leave coco coir out of it, because it holds moisture beautifully and feeds nothing, and an animal that eats its way through its substrate gets nothing back from a floor made of it.
Calcium needs to be permanently available rather than occasionally offered. Cave Cubaris come from limestone, and a species this slow to grow spends a long time building exoskeleton. Cuttlebone or crushed limestone, left in and topped up, is all it takes. Our calcium guide and the longer limestone guide go into which forms are worth using.
Leaf litter and decaying wood are the base of the diet and should never run out. Vegetables in small amounts, occasional protein, and pigment-rich food such as pumpkin and carrot, which is a sensible addition for any colour morph.
Breeding, and what slow actually means
Set expectations before you buy, because this is where disappointment comes from.
Cherry Blossoms establish gradually and produce limited numbers. Suppliers differ on how prolific they are once running, but nobody describes them as fast, and our own experience is that they are slow. Realistically you are looking at months before a new group does anything visible, and a long stretch after that before the numbers mean anything.
What that means in practice: buy the group you want to own, not a starter group you intend to grow into one. Give them stable warmth, stable humidity, permanent food and calcium, and then leave them well alone through the first few months. The commonest way to slow a premium Cubaris down further is to keep checking on it.
Is this the right isopod for you?
It suits three people. The collector who wants something uncommon and is buying it to keep rather than to multiply. The display keeper who wants a premium species that is actually visible. And the long-term project keeper who is comfortable waiting.
It does not suit a first isopod, and it does not suit anyone who needs the colony to pay for itself. If either of those is you, start with a hardy Armadillidium or Porcellio line from our best isopods for beginners guide and come back to this one once you can hold a tub steady through a British winter without thinking about it.
If you are weighing it against the rest of the genus, the complete guide to Cubaris puts the lines side by side, and the Cubaris care guide covers the husbandry in more depth than this page does.
Cherry Blossom isopods are captive-bred here from established UK stock. The rest of the genus is in our Cubaris collection, including the Rubber Ducky and the Panda King.
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