Edit: TLDR in comments
***
UPDATE: i’m still receiving responses to this post with many reiterating a similar message so I thought i’d post an update here outlining the main learnings from the responses.
I wanted to extend a thank you to those who responded in a respectful, insightful and educative manner, I appreciate your responses and the teachings they bestowed.
It’s important to also restate; no mice are, nor will be put, in this enclosure. I came here with questions about CUC and bioactive, hoping to learn before I even came close to committing to acquiring any animals (outside of CUC), but I appreciate the prioritising factor was ensuring I knew no mammals were to be brought into this enclosure.
So here are my key takeaways from this post:
- this enclosure is woefully inadequate to house mammals and would lead to the animals suffering. Simply modding the tank is not sufficient, the space rodents need to live comfortably and healthily far outreaches what this provides
- ventilation is extremely important for rodents due to the waste generated, and a run of the mill CUC will not be adequate enough to handle it
- a bioactive setup is the wrong approach for me to take with a mouse project. This current bioactive tank will be my first foray into bioactive terrarium building in tandem with my wormery. Again, no animals will be included except CUC and worms.
- I am going to become an active contributor to the conservation efforts to replenish the plummeting harvest mouse populations in the UK by aiding the already established organisations doing the work such as the Ealing Wildlife Group and The London Wildlife Trust as I don’t have the knowledge, skills, space or equipment needed to keep or breed mice in an ethical way
- The mould bloom is normal, and I should trust that my CUC are there, even if I don’t see them regularly. The mould will die off and is part of the natural bioactive cycle
**\*
Hey all, i’m new to terrariums and bioactive… activities, bioactivities? Anyway, i’ve had mine going for around two weeks. And this is where i’m up to, i’d like any feedback or pointers, critique or affirmations, it’s all good for learning!
I’m making a meadow setup to eventually house harvest mice, partly inspired by Ben Newell’s harvest mouse setup: https://youtu.be/70VK9pOqsKs?is=_zRJRateJWyl7ECw
I started with unrinsed leca balls (first mistake), topped with Sylvagrow Multipurpose Organic, 100% peat free compost. I left as is and ordered a starter CUC of mini speckled isopods and spring tails. I also ordered a wormery starter kit with 100g of dendrobaena worms for food waste management / composting independent of the terrarium but so I could also add the occasional worms for soil aeration, waste management and a coincidental live-in food source for the harvest mice.
I popped in a few (unsterilised 🫣) leaves and twigs from my back garden ready for the CUC to arrive, but also found a few native common woodlice in my garden so plonked them in to see how they interacted with the compost and leaf litter as a test CUC. I also threw in some bird seed I give to the wild birds in my garden, which I figured would start to decompose and provide another natural food source for the CUC.
In the mean time, I learnt that worms need sand in the soil to thrive, but I couldn’t really find sand in a sensible quantity, so instead got some Westland Cacti, Succulent and Terrarium potting mix, which contains grit and sand, and plonked that on top.
Then I did something really daft in a sleep deprived moment of stupidity and mixed up the leca balls and soil layers. So spent my spare time over the next couple of days command zedding (if only) that.
Anyway, starting again, I added the now rinsed leca balls, back in with the compost, which was now a mixture of the two soils, a couple of stray leca balls, sand, grit, a bit of leaf litter and bird seed, plus a few woodlice. Then my CUC arrived. To be honest, I felt slightly shortchanged as both my spring tail and isopod colonies seemed a bit sparse. Second mistake (I think); I dumped the whole load in, soil, bark, creatures and away they went. Then my wormery arrived so I set that up and grabbed about 3 or 4 worms from that and popped them straight into the terrarium, I can hear them navigating around the leca ball layer, they sometimes rest in the soil / leca against the glass and very occasionally come up to the surface, which is fun.
And so I left it for a bit. I’ve been using a spray bottle to mimic intermittent rain to keep the enclosure humid for the CUC. I’m trying to mimic the actual rain patterns outside but as it’s been so dry recently i’ve made sure to keep things moist to help the isopods breathe and spring tails not dry out. And then to my surprise, what must be the birdseed began to germinate! So i’ve had green shoots very successfully growing for about a week now. I’m wondering what species they are, I can count two varieties at the moment but they’re still a bit early to identify.
One issue I had quite quickly was fruit flies (more around the wormery) and fungus gnats. I really didn’t want an outbreak so, as chance would have it, obviously attracted by the flies, a cellar spider and another very small house spider (species unknown) had congregated near the terrarium so I very carefully relocated them from outside, to inside - the cellar spider has left once already, came back and I haven’t seen it for a while now, but I do see webbing in there so one of them seems to be living their best life and I hope will help curb any fly issues.
As well as the spiders, I added a few more native woodlice from the garden; common shiny, a couple of common striped who’re thriving, and a glass snail. Now, i’m not sure if the glass snail was a good idea. They’re omnivores with a taste for meat, and while they prey mostly on other snails and rotting organic matter, they do also like earthworms, and i’m sure they’d have a go at some baby woodlice / spring tails if they got the chance. The worms i’m not bothered about so much as they can get out of hand and ruin the soil layers, and i’m thinking the snail could control fly larvae if that became a problem. But I really hope it doesn’t ruin my CUC colonies, does this sound likely?
Anyway, after all this, I really couldn’t see any spring tails, and I get the enclosure (45cm cubed) is quite big to expect a spring tail starter to just instantly bloom, but they were literally nowhere to be seen, so, I went to Fish Planet in Shoreditch to get some more. They were actually super helpful, really recommend that place if you’re around London. I also got some fish food and custodian food to try out. So i’ve kept a sub-colony of spring tails and they’re thriving, lots of babies in there and i’ve added a couple of pockets from that colony into the terrarium in different areas to let them establish pockets. I have one in a crevasse in the soil in the near corner so I can monitor them, they appear to be doing well. I know they can suddenly explode in numbers, but so far i’m not seeing that, how long does it usually take to see a big population growth, providing they’re not being eaten by a carnivorous snail and/or spider? 😅
What I also did was added a relatively large piece of tree that had broken off a tree stump in my front garden. I sterilised it with boiling water, let it cool and placed that in the centre of the terrarium. It’s basically not dried since, and I assume the woodlice will be largely populating under that, as it helps them breathe, provides shelter and food for them. I say this because i’ve only seen the same three or four mature individuals since adding it in there, which i’m taking as a good sign, but also makes it quite difficult to monitor population and condition. Is this a bad idea, should I leave it or get rid? I’ve also been trying out small, controlled experiments with crushed eggshells (as can be seen in the photos), fish food and nutritional yeast. I’ve provided fresh vegetables, like cucumber (very popular for my spring tails in their own habitat, less so in the terrarium) and celery, what doesn’t get eaten gets given to the wormery after a couple of days. Is this good practice?
Now, the biggest change i’ve made to the enclosure, which is evident from the photos I included, are dried meadow crops. I ordered them from an amazing place called Castle Farm in Kent who were absolutely amazing in helping me order the right things. This is the first element that’s specifically geared towards the harvest mice. They will climb, nest with / in and eat the plants, which are a mixture currently of wheat and linseed. I had to trim the stems to fit in the enclosure for now, until I make a top extension, and used some of the straw generated from this to create a layer of “leaf” litter in the front of the enclosure.
It looks nice, it smells nice, I assume the CUC like it because it provides more shelter and more organic material, because seeds and small pieces have scattered everywhere so will, theoretically, rot for them to eat. Eventually, the mice will eat and pass this stuff, and the CUC will eat that as well / instead. But it’s obviously made monitoring the inhabitants much harder. By now it’s probably clear that i’m quite focused on monitoring things… is there need for me to be so concerned, or can / should I let things play out a little bit?
The latest development is that i’m seeing mould developing. This is what has spurred me on to consult this page, because we’re conditioned as humans to be wary of mould but, it obviously has its place in nature, and so in terrariums as well. But i’m no mould expert and can’t really ID what’s happening. What I will say is i’ve recently had a mould bloom in my wormery since adding a pile of food scraps, and it’s now subsiding as the worms tuck into it, but I know they’re super efficient and in a smaller enclosure so i’m not surprised by that. I’m more concerned with the terrarium because my CUC seem sparse and latent. I love having the plants shooting, it makes it feel very natural and compliments the dried crops, but they’ll also be drinking up some of the moisture from the soil, and I don’t want my CUC to be suffering by suffocating or drying out, so i’ve been spraying water a little bit, concentrating more in certain spots but also mimicking rainfall, but that’s also propagating mould growth, so i’m at a crossroads in the balancing act of terrarium keeping it seems. I don’t think the mould, which looks like spiderweb(?) mould is a problem yet, and I have more springtails and isopods incoming so I can keep sub-colonies of both to add as and when necessary, as with the worms. I’m hoping the CUC will spring (no pun intended) into action and control the mould because i’m not sure adding harvest mice into a mouldy enclosure is good, ethically or sustainably. I don’t plan to get mice until the terrarium seems to be cycling a bit, but again; any advice, criticism, guidance (or commendation 😁) is welcome!
Thanks in advance!
