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Safely Shipping Isopods Throughout the US Mail System

Updated: Dec 28, 2020

Safely shipping isopods and other invertebrates

Shipping is probably the most stressful aspect of the isopod hobby for many people, but it’s a necessity to distribute the animals throughout the hobby. As mammals, we need a lot of space and frequent meals to survive, so the thought of being in a small dark space with little airflow and food access is terrifying to us. For invertebrates, it is a far different experience – they prefer small, dark spaces, do not require as much oxygen, and eat smaller amounts less frequently. Understanding the needs of the animals being shipped makes the entire process less stressful for everyone. This week, we will discuss our shipping process step by step.

From top to bottom: 2, 4, and 8oz deli cups.

The container to place the isopods in should have enough space for the animals to move around freely. It’s ok for it to be slightly crowded- most species prefer to huddle together even when offered a substantial amount of space. An especially important aspect of the container is that it must have air holes. Although they are small animals, if the container is sealed completely, the isopods will suffocate within a day. We recommend manually making the airholes with something like a small pushpin. Containers can be purchased with pre-punched airholes, but these will typically have a diameter of 3mm or more and isopods can easily escape. A trick that some keepers use is to heat the tip of the pin slightly with a lighter. Although time consuming, this makes it easier to press through the plastic and more of an ergonomic task to prevent sore joints. A larger container will not hurt them, but smaller containers means smaller boxes, which means cheaper shipping. For common smaller species, we use a 2oz container for 10-25 counts, a 4oz container for 50cts, and an 8oz container for 100 to 300cts. Smaller species do fine in smaller containers, so the size does vary. We will put large or sensitive species like the Spanish giant Porcellio hoffmannseggi and Cubaris “rubber ducky” in a larger container to reduce stress in transit. After packing, it is best to securely tape the lid of the container with 2-4 pieces of tape, taking care to make sure that the tape is pressed firmly around the rim. Cups can be ordered from online restaurant supply stores ( is a good source), local restaurant stores, bulk supply stores (like Sam’s club), or online shipping supply stores (we recommend

Sphagnum is our preferred packing material.

The isopods cannot just be tossed in a cup and then in a box – they need something to live in until they reach their destination. The shipping media needs to serve two purposes: hold moisture for the isopods to wet their gills and prevent them from being jostled too much in transit. Remember: It is always better to be too wet than too dry. If the media dries out completely, so will the isopods, and they will die. Some shippers use moistened paper towel to send cultures; it holds moisture well, allows hiding spaces, and fills the cup so the animals are not thrown around the container. We prefer to use sphagnum moss as shipping media and have had a lot of success with it. On a few occasions, some boxes that were unclaimed at the post office were returned to us a month later with all animals intact. Sphagnum functions as a moisture, hiding, and food source. Care must be taken to not pack the cup too tightly; the isopods must be able to move about freely. For common species we fill the cup to the brim (but do not pack it- it is best to be slightly loose), for larger or sensitive species the cup is filled about ¾ of the way. Dwarf species are unavoidably shipped in substrate from their setup because they are so small. We don’t recommend shipping with substrate for any other species as it can pack down easily and cause more harm than good. A layer of sphagnum moss on top of the substrate adds a layer of insulation and moisture for dwarves during their shipping journey. Sphagnum moss can be found in local gardening centers or ordered online. It is best not to include any vegetables, fish flakes, or other food sources that may mold quickly, as the mold can trap and kill the isopods.

There are many shipping boxes available to choose from.

There are a variety of shipping boxes to choose from when sending out the animals. We recommend always using styrofoam insulated boxes when shipping animals, even if the source and destination have ideal weather. This is because the Styrofoam regulates the box temperature and offers structural integrity. If something is dropped on the box (or it is otherwise aggressively handled), the Styrofoam distributes the force, protecting the contents. Shipping boxes can be obtained for free from USPS, but these can only be used with USPS under punishment of federal law. There are boxes that can be purchased from USPS that can be used with any shipping service. Online shipping retailers offer blank boxes for the best price but are offered in quantites of 25 or more. Some people save other shipping boxes, but the sizes are so irregular that it can make finding insulation even more time consuming. Shippers like FedEx also offer shipping boxes but they are quite expensive in comparison to other sources.

Styrofoam insulation that has been cut.

Boxes can be ordered with pre-cut insulation. Shipping supply stores offer them, these boxes are typically brown and blank. USPS offers insulation cut to a variety of boxes you can purchase online. Priority mail boxes are free but must be exclusively used with USPS. Reptile shipping sites like and offer insulated boxes with 1” Styrofoam as well, but these boxes are marked LIVE REPTILE. Not all hubs accept reptiles, so it should be noted that the boxes contain invertebrates. Another option is to order Styrofoam from shipping sites and cut it to fit box dimensions manually. Styrofoam sheets are typically 24" by 48". Styrofoam that is ½’ thick is plenty to protect the animals while still allowing space. Some shippers use up to 1” to be extremely safe, but this sacrifices a lot of space in the box. This is a time-consuming process but can reduce shipping costs of boxes to be only 9% what buying precut boxes would be! We can insulate a 7"x7"x7" box for only 30 cents.

To cut insulation, we recommend using a box cutter. There are styrofoam knives available, but it is possible to get styrofoam poisoning from the burning plastic even while wearing an N95 mask in a well-ventilated area. When the heat on knives is turned up high, more chemicals are released, and the styrofoam melts quickly and irregularly. It is difficult to cut more than one panel at a time with this method due to the knife cooling towards the tip. There are also styrofoam wands, but these are not terribly durable and will break after use on cutting a crate of panels or so. We have yet to break a box cutter (although we have lost…many) on cutting panels in the 4 years we’ve been doing this.

Newspaper is a cheap and readily available packing material.

Newspaper is the cheapest and most reliable option to pack the box securely. It’s an important step to prevent the animals from being jostled around. Oxygen isn’t a concern with a box being tightly packed with newspaper, as long as the cups have airholes there is still some air circulation. Other options to pack the box include packing peanuts and shredded newspaper. Shippers do use paper towels or napking in a jam, but this doesn’t come across as very aesthetic and doesn't crumple or pack well. Newspaper also functions as an additional level of insulation, when packed firmly it encourages temperature stabilization and protects the box contents.

From left to right: Cryopak, cold pack, 40 hour heat pack and 72 hour heat pack.

When temps are outside of the normal range, stabilization packs are added to ensure the survival of the animals. There are 3 options available: Cryopak/phase22 packs, ice packs, and heat packs. There are also additional varieties of heat pack available that are 40 hour and 72 hour. Cryopaks contain a unique material that likes to maintain itself at 72F; below 72F it is a solid, and above it is a liquid. They are expensive but one of the best shipping tools available. Important: do NOT use handwarmers to heat animals in transit. These are not for use in small confined spaces, reach high temps and will likely kill the animal. A good tip to remember when shipping is that animals are more likely to die from heat than they are from being too cold, so it is best to not use heat unless absolutely necessary and to use cold whenever in doubt. We recommend only using heat when temps are below 40F at either end, and we add a cold pack to the box if temps are above 70F. We add an additional Cryopak if temps are above 90F, and if the destination temps are above 105F we recommend not shipping until it cools down. Cryopaks are also useful for those tricky in-between temperatures or when one side of the shipment is cooler or hotter than another. Cryopaks can be heated in warm water to provide a heat source, then typically will firm up by the time they reach their destination to provide a cooling source. When using Cryopaks or cold packs, we recommend placing the packs in ziplock-type plastic bags as these have been known to burst in transit from faulty seams. If animals or their containers are coated with the contents, this will result in certain death. When using a heat pack, wrap in several layers of newspaper and make sure that there is newspaper to insulate the animals from too much heat. Heat packs can reach temps above 120F. Another aspect to note is that heat rises so do not place the animals on top of the heat pack – instead the safest method is to securely tape the pack to the top panel so it does not press and overheat the animals. For the safety of the animals, if destination temps are below 30F or above 80F, we recommend having the box held at the shipping hub, because the shipping vehicles are not temperature controlled, and if the box of animals is sitting on the steps in front of the house in the sun, the contents can reach over 100F in less than an hour.

The shipping service is up to the discretion of the shipper; the more expensive services have less risk of loss, damage, or delay, but they’re more expensive. USPS is the cheapest option on the market, but many people have difficulties picking up held items from post offices. Since the onset of the coronavirus crisis, shipments have been delayed 10 days or more, or have been lost in the system and returned to sender. Although cheap, there is a significant amount of risk with USPS, and we personally do not recommend using USPS for live animal shipments. Labels for USPS can be purchased directly from the USPS website, or from secondary services such as or for a discounted rate. FedEx is currently the most reliable service on the market- but for as much as 3x more than USPS in some instances. UPS (not to be confused with USPS) is another available service that is midline on expenses- slightly more than USPS but less than FedEx. We don’t have any complaints about FedEx or UPS and have switched our shipping options for live animals over to them entirely. Labels can be purchased through shipping sites ensured to ship reptiles like or, or directly through the FedEx and UPS websites. Labels can also be printed at the service window, but it is a lot easier to do it from the comfort of your home and drop off the package.

Business cards add a nice touch to any order.

Now that the contents of the box are secured and comfy, it’s time for the finer details. Including business cards adds a nice professional touch to the box, and many people appreciate a handwritten note. An invoice detailing the contents of the box is a useful reference to both the shipper and the receiver.

This week's blog post is a bit dull, but we hope that it will serve as a good reference for both those new and experienced in shipping isopods. Thanks for reading!

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Forest Gamp
Forest Gamp
Oct 11, 2023

Safely shipping isopods throughout the US mail system requires a reliable logistics partner. Real Trucking, a trusted name in the transportation industry, plays a crucial role in ensuring the smooth and secure delivery of these delicate creatures. Their expertise in handling sensitive cargo and commitment to safety make them the ideal choice for such shipments. Real Trucking's meticulous approach and efficient transportation solutions provide peace of mind to those sending or receiving isopods. With their assistance, these fascinating creatures can be transported with care, ensuring they arrive at their destination in perfect condition while complying with all regulations and standards.


Ariel Tarrand
Ariel Tarrand
Jul 16, 2023

This was so helpful, thank you!! I'm considering starting a small isopod business, and this was the most comprehensive shipping guide I could find.


Nathan Adrian
Nathan Adrian
Jun 23, 2023

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Beth S
Beth S
May 22, 2023

I realize this is a rather old blog post (and according to the author “a bit dull”), but I wan to thank you so much for the information. I’m very new to selling/shipping isopods but I’ve had them for a few years now and have grown quite fond of them; I don’t want to do them any harm by mailing them. Your article was informative and helpful and gave me things to consider that I’d not previously thought of.


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