Unlike other terrestrial arthropods you may be more familiar with, isopods have gills or gill-like structures. If there is no water available, isopods will not be able to breathe. The humidity in your culture must also be appropriate to the species. High humidity species will have trouble breathing and molting if the culture is too arid, and vice versa. Regardless of species, though, moisture must ALWAYS be available in your culture. 

Most keepers will establish a moisture gradient, which allows isopods to self-regulate. One side of the enclosure is the "wet" side and the opposite side is the "dry" side, and the isopod can choose which side it needs to be on. Sphagnum moss is usually added to the substrate on the "wet" side to retain moisture. At IsoParty, we also like to make sure both the wet and dry sides have cork-bark hides. We want our isopods to always feel protected.

Ventilation is overlooked too often when it comes to isopods. We cannot stress the importance of adequate and appropriate air flow! Vents should be located on the SIDES of your enclosures to promote cross-ventilation. Speaking generally, you should only have vents on the top of your enclosure if you also have side vents. Vents located on the lid of an enclosure do not allow air to circulate and be refreshed effectively. This can cause a dangerous build-up of ammonia that can crash your cultures. Care may also have to be adjusted as the seasons change, depending on the conditions in your dwelling. 

As a general rule of thumb:

If you notice all of your isopods are cramped together on the dry side of the enclosure with NO isopods found on the wet side, you are probably keeping this culture too moist. Cut back the frequency of watering or the amount of water you're adding. You can also remove some of the sphagnum moss or increase the amount of ventilation. 

If all of the isopods are cramped together on the wet side of your enclosure with NO isopods on the dry side, you are probably keeping this culture too dry. Increase the frequency of watering or the amount of water you're adding. You can also increase the size of the wet side by adding more sphagnum moss. For some of our species that really love moist substrate, we may also moisten the "dry" side, but this is done as needed.

Sometimes it can be helpful to be reminded that soil humidity and air humidity are two separate parameters. Some species may prefer soil that is consistently moist, but still require higher ventilation. Many Cubaris isopods are like this. 

Balancing humidity and ventilation can be very tricky as we all tend to have "microclimates" in our dwellings. You may live somewhere with naturally high humidity, but keep your isopods near an air vent. You may live somewhere arid, and have a shelf near a bathroom that might stay more humid. You will have to learn to balance humidity and ventilation for your specific situation. As you become more familiar with keeping isopods, you'll understand how to modify their enclosures to fit their needs.

Some keepers may choose to purchase a hygrometer. This device will measure the humidity in the air. You can find a myriad of digital or analog hygrometers online or in your local pet shop, and they come at a variety of price points. Fancier models can be attached to fans and mister systems and will automatically activate whichever device is necessary to maintain a set humidity. While we do recommend looking into these more advanced controllers for reptiles, amphibians, or larger terrariums, just a basic analog hygrometer will do the job for your isopods.