Setting up a suitable home for giant millipedes doesn’t need to be very difficult or complex, as long as you keep a few key considerations in mind. In their natural habitat, millipedes typically live on the forest floor or on logs, and prefer relatively high humidity. Also, since they are docile and non-territorial, multiple millipedes can be housed peacefully together in the same tank.
Choosing an Enclosure
For tank setup, a simple, standard 5 to 15 gallon aquarium tank makes for a perfect enclosure. The size you choose will depend on how many millipedes you have. If you only have one or two, then a 5 or 10 gallon tank will work great. If you have several or more, you will probably want a 10 or 15 gallon tank.
As far as the dimensions of the tank go, you’ll want to make sure that the tank is at least twice as long as your longest millipede (if they aren’t fully grown yet, don’t forget to take into account their full adult size!).
It’s recommended not to choose one of those tall, vertically oriented tanks. A normal, standard shaped tank that is wider/longer than it is tall is much better. Millipedes spend most of their time plodding around on the ground, so floor space is much more important than vertical height.
Whatever tank you choose, make sure that it has a lid, especially if you add things to the tank that could be climbed (like plants, large rocks or pieces of wood). The lid should be able to be secured fairly tightly, not simply a flap like the kind found on many aquarium lids meant for fish. Otherwise, your millipedes may be able to push it open, crawl out of their tank, and start exploring around your house!
Substrate is Important
It’s vital to have a fairly deep layer of substrate filling the bottom of the tank. Ideally, it should be about as deep as your millipede is long (or at least four or five inches), since they like to burrow sometimes. In addition, if your millipedes are not fully grown yet, they will molt at some point. During this process, they often like to burrow down into the substrate, since otherwise they would feel very vulnerable and exposed.
They also like to burrow in order to lay their eggs, so if you are hoping to breed them, make sure you have a sufficiently deep substrate.
You can use organic potting soil or compost mix for the substrate base, as long as it doesn’t have any added fertilizer, pesticides, or herbicides, as some garden soils do. Peat moss is also a great addition to the substrate.
Millipedes need a source of calcium to stay healthy, and you will probably want to provide this separately with their food, but you can also mix a little calcium powder directly into the substrate as well.
The most important part of the substrate is a layer of decaying leaves (and broken up wood) from hardwood trees (avoid using wood from soft wood trees such as pines). This should make up the top most layer, but should also be mixed in throughout the depth of the substrate as well. Moss makes a great addition too!
Definitely avoid things like aquarium gravel, since it will be difficult for your millipedes to dig through. Whatever your mix of substrate is, it should be kept loose and airy, not tightly compacted or hard.
As far as maintenance is concerned, completely changing out the substrate should rarely be needed (unless some sort of pest outbreak occurs), but you should top it off with some new leaf litter on top about every month or so.
Giant millipedes prefer temperatures from about 70 F to 80 F (21 C to 27 C) degrees, but their specific temperature needs will vary between species. More tropical species will do better in the 75 F to 80 F (24 C to 27 C) range, while species from higher latitudes will generally prefer about 70 F to 75 F (21 F to 24 C). Equipping the tank with a small digital thermometer is an easy, convenient way to make sure you’ll always know if things are getting too cold or too hot.
If you live in a cooler climate, or like to keep your home on the cooler side, you may be tempted to add a heat pad to keep the tank a little warmer. However, this can be dangerous! When millipedes feel too hot, their natural instinct is to burrow down into the ground to cool off. If you have a heating pad underneath the tank though, they’ll just keep digging down deeper and deeper, bringing them too close to the pad until they overheat or become dehydrated. This could kill them! If you must use a heating pad, attaching it to the side or back of the tank instead is a safer option. This will also prevent the pad from drying out the bottom layer of the substrate.
The humidity in the tank should be kept relatively high (but not too high). You may need to periodically mist the substrate with a spray bottle (be careful not to use chlorinated water for this), especially if you live in a dryer climate. The substrate should be kept damp, but not wet. If you pick up a handful of it, squeeze it, and see water dripping out, then it is too wet.
If the tank has improper humidity levels, it could lead to problems like fungal infections and disease. Having the humidity be too wet or too dry can both cause a whole host of health problems for your millipedes.
The tank should be kept out of direct sunlight, as this can cause the soil to become too dry. Additionally, millipedes naturally shy away from bright lights, instead preferring a shaded environment (since this is where they typically find food and avoid predators in the wild). If their tank is constantly being illuminated with bright lighting, you may not see them as often, since they will likely hide down in the substrate out of view.
Your millipedes will definitely enjoy having some things to hide under in their tank. They don’t need much, but some bark (cork bark is ideal) or pieces of light-weight wood will give them some nice, cozy hiding places and provide them with an opportunity to climb around if they want.
Rocks, large pieces of wood, and other heavy objects should probably be avoided entirely. Millipedes will likely burrow underneath them, and if these heavy objects shift in the soft substrate, it could crush and injure them, especially when they are at their most vulnerable during molting.