Meet the Super Cute (and Super Rare) Rubber Ducky Isopod!

These days, the Rubber Ducky Isopod is the darling of the bioactive terrarium world, and for good reason.

I mean, just look at them…

With their cute yellow duck faces and painted tails, they bring so much character (and usefulness to a terrarium).

Only recently discovered in Thailand, the new species – Cubaris sp. Rubber Ducky – was found in limestone cave areas so they have some unique care requirements compared to other isopods.

Find out where to find these beautiful creatures for yourself and how to care for them!

Rubber Ducky Isopod on cork bark

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Rubber Ducky Isopod Lifespan, Behavior and Growth

Part of what makes these critters so rare is that they’ve been quite challenging to breed in captivity. They can take a fair few months to reach maturity, so it can take a while to produce enough for breeders to sell.

These cuties will grow a little bigger than the typical terrarium dwarf isopods, but they should max out around 2cm long so they’re still suitable for most reasonably sized terrariums/culture bins.

rubber ducky isopod on leaf
These adorable little critters are really quite chill.

They also seem to be quite shy, and there are plenty of worried Redditors asking if their broods are okay because they haven’t seen them much in weeks!

Thankfully, Rubber Ducky Isopods reportedly can live for years with good care. Though, with them only discovered in 2017, that doesn’t give us a lot of lifespan data to work with…

Where to Find Rubber Ducky Isopods for Sale

Well, here’s the real question…

While Rubber Ducky Isopods have been hard to find historically, the team at specializes in them (as you might expect by the name)!

They often have stock, so I’d definitely check there first. 👇

Our Top Pick
Rubber Ducky Isopods (Cubaris sp) 6 Count

Securely shipped in a culture start-up system that contains: Organic Sphagnum Moss, RDI House Blend Superfood, and Sprinkled Oak Leaves.

From our partners, Rubber Ducky Isopods. (Shipping included).

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Other Cubaris Isopods for Sale

Interestingly, there’s a wide variety of new Cubaris species being discovered. In fact, the Rubber Ducky Isopod hasn’t even been officially classified yet.

So, if you’re curious (or can’t get stock of Rubber Duckies just yet) here are a few other cool species you can check out too.

Rubber Ducky Isopod Care

With Cubaris sp. Rubber Ducky being a relatively new species, people have been experimenting a lot to find the best conditions to care for them.

These orange-faced beasties tend to prefer damper conditions, moderate temperatures of 70-80°F (21-27°C), and higher humidity – which arguably makes them an excellent fit for tropical terrariums.

Though granted, they’re typically kept as an isopod pet rather than a bioactive custodian.

rubber ducky isopod on twig

The following recommendations are a curated mix of supplies, foods, and substrates that expert isopod owners and shops have found success with.


Rubber Ducky Isopods reportedly like/need quite a varied diet.

Though they seem to prefer natural sources of decaying wood or leaves (e.g., leaf litter) rather than scraps from your meals, you’ll likely still need to supplement their diet with a protein source and, ideally, some limestone (more on that last one later).

rubber ducky isopod face
Leaf litter is an isopod staple (also, look at its little face!).

For protein, some people like to add dried fish, either whole (small ones like minnows) or in a flake form. It’s worth experimenting to see what they like, and start small, as you don’t want your terrarium full of rotting food.

👉 This crab meal product is a convenient way to tick all those boxes!


Substrate recommendations mostly fall in line with typical terrarium mixes but with a few added supplements. Here are some personal recommendations from experienced isopod owners.

“25% coco fiber, 40% chunked rotting wood, 15% leaves, and, 10% dried sphagnum moss, and finally about 10% pulverized limestone.”

@Derposour on Reddit

The coco fiber and sphagnum moss will help to maintain the higher level of moisture they prefer, and the wood and leaves are their primary food source.

rubber ducky isopod on sphagnum
An area of pure sphagnum moss can help them regulate their hydration too.

The limestone is an interesting one, though.

In order to accurately recreate their natural environment, people have been adding limestone to the substrate mix with great results.

Limestone is a sedimentary rock that’s made up primarily of calcium carbonate, which they use to build their exoskeletons. Thankfully for us, calcium carbonate is actually a common gardening supplement that often goes by the name of “Garden Lime.”

It’s typically used as a soil supplement to increase the pH for plants, but it’ll work a treat here.

Finally, with their shy nature, rubber ducky isopods seem to like a deeper substrate layer that they can burrow into. If you’re establishing them separately from a terrarium, you can use these great acrylic invertebrate enclosures from EZbotanicals.

Image courtesy of EZBotanicals on Etsy

Over to You

Have you been one of the lucky few to get your hands on the Rubber Ducky Isopod?

Let us know how you’re getting on in the comments!

Or, for more funky isopod inspiration, check out my Isopod Species Guide.

About The Author

5 thoughts on “Meet the Super Cute (and Super Rare) Rubber Ducky Isopod!”

  1. Hey, since we don’t know much about this species since it was only discovered a few years ago, I thought I might say that I got babies from my Rubber Duckies. I noticed them yesterday, two months after I bought the parents. One of the females must have already been pregnant, but I figured it was also possible that they might have somehow reproduced quickly.

    1. I have 9 and they FINALLY had babies. I use dolomite mix and a cuttle bone for my isopods…I also make a isopod mix that is hard wood pellets (untreated) spagnam moss topsoil (organic) dolomite, and ground up leaf litter (i harvest from a local swamp that doesnt use pesticides) I had 7 months and noticed babies yesterday!

  2. I saw 1 baby after 2 weeks of getting duckies, not sure if there’s any more. Unfortunately 1 adult passed away 2 days after I noticed mancae. It’s hard to say the reason, 5 of them seems to be full adult, not sure their age, maybe they are old. Hopefully it wasn’t environmental cause and I won’t see any more deaths.

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