Bioactive hamster care is a subject that isn’t widely explored yet. So I would like to preface this with it not being the type of care for everyone and not something to do without properly thinking about cost and possible negatives that can occur in the process. I started my research into bioactive enclosures as I was curious how to make my hamster's life more natural and enriching.
What is a bioactive enclosure?
A bioactive enclose is a self-contained ecosystem aiming to provide as close to the inhabitant's natural environments as possible in an enclosure. This will utilise a soil type substrate, plants and detritivores known as the cleanup crew. All of these components are needed to create a functioning nitrogen cycle and have a healthy system.
Substrate
Having a good substrate is important for your hamster to be able to perform natural behaviours the same for any enclosure. For substrate, there is no set recipe for mixing as everyone has access to different things and have slightly different preferences, the reptiles that use similar arid substrates to the one you would use for a hamster are Leopard gecko, Bearded dragon and Uromastyx. Mammals that are sometimes kept bioactive and would have a similar substrate mix would be African pygmy hedgehogs and tenrecs. Different species of hamsters will also need slightly different mixes with Roborovski hamsters liking the top layer being much sandier maybe even a dressing on the top of pure sand and Syrians are from more agricultural land so will be slightly less sand in the mix. There are several criteria that you need to meet for any substrate they are:
Drainage the substrate has to have good drainage to ensure your hamster isn’t living in a wet environment as they are from largely dry environments such as deserts and steppes. In many reptile bioactive setups, people will make a drainage layer of something like clay balls and cover it with a fabric barrier so the soil and drainage layer don’t mix I don’t think this is a sensible idea for hamsters as they are likely to have issues with digging into the barrier.
Structure the soil needs to hold burrows well without getting compacted so that the plants can still root and hold well.
Non-toxic it’s easy to achieve the substrate being nontoxic as a large proportion of it will be things you could already in your hamsters cage such as play sand and coconut coir (eco earth), other things you could add is organic topsoil with no additives such as perlite or fertilisers, and excavator clay can help the soil hold burrows.
Leaf litter is a very important part of the substrate layer it separates the inhabitant from any dampness in the soil and provides a barrier between the cleanup crew and the hamster preventing as many from becoming food. It is also an important part of the ecosystem breaking down into the soil and providing nutrients for the plants to thrive.
Plants 
The plants are an important part of the nitrogen cycle and are completely necessary for a bioactive ecosystem to convert the waste from the animals and remove nitrates from the soil. They also add a good amount of cover so can be very beneficial for shy hamsters and make them feel more secure. Many plants can work in a hamster enclosure but you have to make sure all the plants you use are non-toxic as they are likely to eat some of the plants whether that is roots or leaves. The plants will also need to be drought-tolerant and hardy as plants can be hard to keep alive with hamsters burrowing and eating vegetation, this means there can be regular plant deaths so the price may be also something you want to take into consideration. There are many types of plants that can fit these criteria:
Grass nearly every type of grass is safe for hamsters and easy to grow, many can be grown from seed and can cope with low water levels this means that you can keep growing new plants outside the enclosure when a hamster either digs them up or eats them. Carex varieties of grasses are the most drought-resistant but you can easily grow any type of grass with a little effort.
Seeds Just growing some seeds from your hamster's mix is also an easy way to incorporate plants in your hamster's enclosure as these will be safe and sprout well (or should if you are feeding a good mix), they may not be super drought tolerant but if you find your hamster eating all of their plants it can be good to know they are only eating plants grown in a safe environment.
Succulents are a type of plant that very much fit into the niche that hamsters live in but there are only a few that are suitable as many have large spines that could be dangerous to a hamster or have toxicity concerns. Opuntia, Sempervivum, Haworthia, and Echeveria are all non-toxic types of succulents. Opuntia in particular is regularly fed to tortoises and is edible.
Plants can benefit from a period of bedding in so if planning on setting up a bioactive enclosure it is best to do between hamsters or if you have a separate enclosure to keep your hamster in for a bit when everything is settling. This period will be similar to setting up a fish tank as it gives time for the nitrogen cycle to get started as well as the plants to settle and can take up to 8 weeks.
Lighting is also a concern when setting up any plants inside as many will require more light than they would get being in a hamster enclosure with natural light. The light that you choose would need to be on a timer so that it would not be on during the night and likely need to be a white full spectrum LED there are many types available, many that work in fish tanks will work in this situation.
Clean up crew 
The cleanup crew are small detritivores that will consume waste material in your enclosure. There are varying creatures that will work as cleanup crew worms, beetles, isopods and tiny insects (technically hexapods) called springtails. You can use any number and variety of cleanup crew you want, springtails may struggle with too low moisture so a variety of isopods and beetles are your best bet.
Worms whether the more typical earthworm or mealworms can work well as CUC as they move through the substrate it can add aeration which can prevent stagnation. Earthworms and red wigglers may struggle with how dry the soil will be but if they have a small area where they can use as a refuge in the soil they should be able to cope. Mealworms work well and when they pupate the beetles are useful too. The only issue with worms is many become food as they have fleshy bodies.
Beetles can be as simple as mealworm beetles they are easy to get hold of and your hamster won’t come to any harm eating a few, buffalo worms(or lesser mealworms) and even the more expensive blue feigning death beetles can work, as they have low humidity requirements.
Isopods are an interesting creature in their own right and there are hundreds of types and many of them are too expensive to use for a bioactive enclosure, I have had luck with breeding Armadillidium maculatum(zebra isopods), Porcellio laevis both dairy cows and orange types, and also Porcellionides pruinosus(powder blue isopods). I would also expect Porcellio scaber to work well as they are a fast-breeding isopod that will fit into many niches. I haven’t had any struggles with parsnip my current hamster eating isopods and they are haply breeding in the area of her cage I have as a mini bioactive section. You do need a good selection of places for your isopods to hide so having cork flats and rounds are good for them to hide on the bottom of they also need a bit of humidity when they shed so having a corner that you spray with water every couple of days is appreciated by them, I tend to do this first thing in the morning when most of the water will be absorbed into the substrate by the time the hamster is most active.
Due to hamsters eating insects it is advised that you keep a separate container of your CUC so that you can repopulate your enclosure as needed.
The problems
There are a whole host of problems that can occur when creating a bioactive enclosure for any animal and even more when creating one for one with such specific needs such as a hamster.
Pest can be a major problem in enclosures. Fungus gnats, soil mites and fungus itself can all become problems if the watering of the enclosure is off or if you haven’t got the correct balance of CUC.
Weight the weight of a bioactive tank will be comparable to the weight of the enclosure full of water (heavy!) this means if you ever need to move the enclosure you will either need wheels or empty it.
Cost/access to materials it can be hard to source materials that are suitable to place in a hamster enclosure when just trying to create a more typical enclosure. It can be doubly hard when making a bioactive enclosure with sourcing plants and insects that could potentially have been stored in a way that is not hamster safe so you must buy your plants from a place that sells them for animal enclosures or grow your own. I also think it’s best to let your isopods breed for a couple of generations before placing them in the enclosure. All of these things add to the cost of creating a bioactive enclosure.
You still may have to clean. This isn’t something people expect with a bioactive enclosure but with mammals, the high waste load may be too much for your CUC so you may still need to spot clean the pee areas.
Conclusion
To conclude creating a bioactive enclosure is a very interesting undertaking but can be very time consuming and there are many potential problems. The enrichment that this can provide for the hamster may overwhelm cons for many.
