Isopods come up as a necessity for bioactive; after all – it isn’t very active if the base layer of cleaners isn’t present. A big question is, what is the best way to introduce isopods? Is there a right way and a wrong way to do it? Isopods can be expensive, especially compared to feeders like crickets and mealworms, and starter cultures are often very small, so it’s best to proceed with caution and not lose a large part of the starter population.
A good guideline that people follow is the rule of halves – when first receiving a culture, put half in the terrarium, and half in a reserve tub to culture separately. We recommend only using this method if the starter culture is 25 animals or more, or a large, seeded culture of 8oz by volume or more substrate (many dwarf species, for example). Once the terrarium is seeded, it is best to allow the environment to “cycle”, meaning regulate itself for 1 and ideally 4 weeks, before introducing the main attraction of large animal, such as geckos or other reptiles. This allows the isopods to burrow, hide, breed, and otherwise establish themselves. It also allows another level of micro fauna – bacteria, and ideally springtails if they were added – to populate the tank. These micro fauna encourage the isopods to further thrive and create a healthier environment to further break down animal waste.
Now, on to setting up the reserve tub. This tub doesn’t have to be large, just enough to culture a separate population to re-seed the terrarium from time to time. We recommend a plastic 6qt shoebox (5.7L). Set it up like a typical isopod setup – 1” of dirt, a generous layer of leaves, and a bit of egg crate or bark. Adding supplements like protein and calcium will encourage the population to grow better, which creates a healthy number of isopods to pull from to reseed the tank. Reseeding is an important part of bioactive, because the main attraction will typically eat the isopods, or if the substrate becomes waterlogged, they may die off. The egg crate and cork is especially important, because it is a great method to monitor the population in the tub. Isopods gather on the crate together, making an easy method to estimate the population and harvest them. To harvest the isopods for a terrarium, gently tap the opposite side of the crate into a tub or directly into the terrarium.
When adding isopods to a setup, be sure to place them on the surface and allow them to meander from there. If also adding moss or substrate with the isopods they may have been shipped in, gently spread the material out across the surface. It is very important to not put additional substrate on top of the isopods because burying them can suffocate and kill them. Although they do burrow, without a clear burrow and way to the surface they will die. If the desired effect is to hide substrate or moss the isopods were in, leaves can be placed over the area the isopods were released. To prevent the isopods from being eaten, allow the isopods to disperse throughout the setup for 1-4 hours in an established tank before releasing a larger animal that may eat them.