# Communal invert tank



## Creobroter (Jul 1, 2017)

Hi,
I'm currently creating a communal invert tank (various different inverts that will not harm one another in one tank, millipedes, beetles etc). Anyone have any suggestions on what species would be good?


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## Aquarimax (Jul 1, 2017)

Isopods and springtails! Isopods  have sometimes been known to after large millipedes after a molt, but I suspect they'd be fine with smaller ones.


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## Crowbawt (Jul 4, 2017)

I haven't had any issues keeping a couple ornate harvestmen in with my millipedes, but I've only had the tank going for a few months so take that with a grain of salt. They feed on the springtails and fish pellets I occasionally put in.


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## DubiaW (Jul 5, 2017)

Try setting up for some vertically inclined specimens. Small amblypygi wouldn't bother them. Maybe some small mantid species, jumping spiders, an ogre faced spider or _Centruroides gracilis _to take care of any flies that are attracted to the fruits and veggies you feed your millies. That way you have a little food web for pests and the like. I've never done something like this but I have been thinking about it. How about some _Blaptica gigantea_?

Reactions: Like 1 | Agree 1


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## spotropaicsav (Jul 5, 2017)

DubiaW said:


> Try setting up for some vertically inclined specimens.


I like this idea. Not only for the practical reasons, but also visually having activity at different levels in your enclosure sounds pleasing.


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## Creobroter (Jul 5, 2017)

Crowbawt said:


> I haven't had any issues keeping a couple ornate harvestmen in with my millipedes, but I've only had the tank going for a few months so take that with a grain of salt. They feed on the springtails and fish pellets I occasionally put in.


Do the harvest men breed?


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## Creobroter (Jul 5, 2017)

DubiaW said:


> Try setting up for some vertically inclined specimens. Small amblypygi wouldn't bother them. Maybe some small mantid species, jumping spiders, an ogre faced spider or _Centruroides gracilis _to take care of any flies that are attracted to the fruits and veggies you feed your millies. That way you have a little food web for pests and the like. I've never done something like this but I have been thinking about it. How about some _Blaptica gigantea_?


Would the predator species not bother each other?


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## DubiaW (Jul 5, 2017)

Creobroter said:


> Would the predator species not bother each other?


You would have to chose which ones you wanted carefully. I was just throwing out some ideas that popped into my head. If you were careful about choosing certain species that had completely different habits you could cohabitate predators. For example it might be possible to keep nocturnal terrestrial scorpions with arboreal diurnal spiders. It would be important in this case to have a grow light to maintain the circadian rhythm of your specimens. Without natural sunlight a lot of my nocturnal T's and chilopods don't bother to burrow even though they have plenty of substrate and or hides. 

It would be really neat to have an spiny orb weaver in a large setup like this. There are some stunning _Gasteracantha _sp. species that are readily available in southern Texas that would be great display animals but would take a large terrarium to house properly. A interspecies communal could justify a large setup like that. They could probably be housed with a variety of things that wouldn't get caught in their web.

Reactions: Like 1


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## spotropaicsav (Jul 6, 2017)

DubiaW said:


> You would have to chose which ones you wanted carefully. I was just throwing out some ideas that popped into my head. If you were careful about choosing certain species that had completely different habits you could cohabitate predators. For example it might be possible to keep nocturnal terrestrial scorpions with arboreal diurnal spiders. It would be important in this case to have a grow light to maintain the circadian rhythm of your specimens. Without natural sunlight a lot of my nocturnal T's and chilopods don't bother to burrow even though they have plenty of substrate and or hides.
> 
> It would be really neat to have an spiny orb weaver in a large setup like this. There are some stunning _Gasteracantha _sp. species that are readily available in southern Texas that would be great display animals but would take a large terrarium to house properly. A interspecies communal could justify a large setup like that. They could probably be housed with a variety of things that wouldn't get caught in their web.
> View attachment 245116


Very nice pics


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## Crowbawt (Jul 13, 2017)

Creobroter said:


> Do the harvest men breed?


I've observed some courtship behavior but nothing more than that yet. They're only been in with the millipedes a month or so though. 

I believe they've also been eating fruit fly eggs/larva that have gotten on the fruit for the millipedes, gonna try to confirm that if I can. They're secretive eaters but as far as I can tell completely ignore the millies.

Reactions: Helpful 1


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## davehuth (Mar 13, 2018)

Creobroter said:


> Hi,
> I'm currently creating a communal invert tank (various different inverts that will not harm one another in one tank, millipedes, beetles etc). Anyone have any suggestions on what species would be good?





Crowbawt said:


> I haven't had any issues keeping a couple ornate harvestmen in with my millipedes, but I've only had the tank going for a few months so take that with a grain of salt. They feed on the springtails and fish pellets I occasionally put in.


Hello @Creobroter and @Crowbawt , communal enclosures are in interest of mine and I was wondering how yours are coming along? I have had local Harvestman species appear in mine from unsterilized substrate, and I'm finding they add a lot of interesting visual and behavior appeal. I'd be interested in hearing about any issues/problems/unexpected delights in your communal enclosures (here or in a direct message). Thanks!


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## Dennis Nedry (Mar 13, 2018)

I've kept White tailed spiders in with millipedes and roaches as they only eat other spiders.
Think of it this way, if I take a jumping spider or a small mantis it's not going to bother a 20+ cm giant millipede. A small scorpion or amblypygid is not going to bother a large phasmid, etc, etc.

Think of some communald you might want to try and post them here so people can try give advice

Reactions: Like 1 | Agree 1


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## Abbio (Mar 28, 2018)

Hey! really happy to have found this thread as i have just created one myself but i haven't had any responses, be great to get this discussion going again. 
I cant seem to talk to anyone about this subject and i really want to learn from your exp before trying it myself! 

What i wanted to put together was:
Madagascan Banded Millipede
Sun Beetles
Orange woodlouse
Springtails

Could this work well?

What sub would you recommend?

And what maintenance would i need to do ? and how often?


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## LawnShrimp (Mar 28, 2018)

Abbio said:


> Hey! really happy to have found this thread as i have just created one myself but i haven't had any responses, be great to get this discussion going again.
> I cant seem to talk to anyone about this subject and i really want to learn from your exp before trying it myself!
> 
> What i wanted to put together was:
> ...


A substrate as deep as the longest millipede is recommended. Larvae of sun beetles will need a substrate rich in rotting material like grass clippings and vegetable scraps (which millipedes do not do well in), but adults would much prefer the millipede substrate. The beetles might lay eggs which develop into substrate-gobbling machines. Orange woodlice are most likely Porcellio scaber or P. laevis, both of which are voracious and will consume millipede and beetle eggs, as well as molting millipedes. They also breed very quickly and a couple Porcellio can produce as many as 50 babies each, which all contribute to the consumption of the substrate. Springtails are pretty much inoffensive to everything and a great addition to any vivarium.

You could probably make this work but adding lots of decoration such as bark, leaves, and sticks will keep each inhabitant occupied and isolated so they don't bother each other much. I do advise tossing a few fish flakes or dog food pellets in there every now and then; this will keep the isopods full of protein and also make a nice milli treat. Important maintenance would be removing a handful of woodlice when the population explodes. You will also have to replace substrate more often than a solely millipede tank as there are many organisms eating it.

Reactions: Agree 1


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## davehuth (Mar 28, 2018)

Abbio said:


> What i wanted to put together was:
> 
> Madagascan Banded Millipede
> 
> ...


Hello! Nice to hear you're interested in trying a communal enclosure. One of the things I like about nature is ecological interactions, and I'm currently enjoying a 20 gallon tank housing multiple genera of inverts. However, the experiment has run only about 4 months. Long term sustainability is uncertain.

Below are some suggestions. I'm not an expert. I take a lot of notes on my enclosure, so I’ve included a lot of information. My hope is to encourage others to give it a try, and to share their experiences. I don’t think this is an especially common practice in the hobby, so there are many unknowns.

1. ISOPODS
I'd be uneasy about including isopods, because they can exert a surprisingly strong force within the boundaries of an enclosure, especially as their numbers grow. Although they're primarily detritivores, they can be opportunistic and  indiscriminate at times. One threat they may pose is to millipedes, for example when the millipedes are moulting, or when young millipedes are very small. Most experienced millipede keepers I've communicated with avoid keeping isopods and millipedes together. Different species of ispods vary in their habits, so there might be a species that would do fine communally. But I'm not aware of experiments being tried to determine this. That being said, TarantulaAddict on Youtube (also one of my inspirations) has had isopods in his communal tank for a while so we could ask him how it’s going. I use springtails to control for molds, etc.

2. SUBSTRATE COMPONENTS
I use a basic rich and varied millipede substrate based on @mickiem 's "Fussy Substrate Recipe" (you can search it up easily here on AB). It's essentially 1/3 coconut fiber, 1/3 decomposing oak leaves, 1/3 decomposing hardwood. I let a lot of other stuff stay in there, such as any mosses or lichens clinging to the wood I grind up, because I never know what multiple species might find tasty.

3. SUBSTRATE STERILIZATION
This is controversial, but I don't sterilize the substrate. With so many species interactions, I want to replicate something a little closer to a natural ecology, including fungal colonies, terrestrial algaes, and other microbiota. This is a risk, notably because of predators popping up. Predatory animals are a natural part of ecological relationships, but because of the constrained size of the tank I don't trust that I can balance these relationships. I'm partial to non-predatory invertebrates anyway, so I watch everything like a hawk and remove anything that concerns me. This includes every ant, unidentified beetle, every grub that crawls out of a stick, baby centipedes, stray isopods, etc. I know there may be an undetected, deeply burrowed monster at the bottom of the substrate slowly picking off creatures I want to preserve, but this risk is simply part of the way I've decided to run the enclosure at this time, so I'm vigilant and hoping for the best. You should be able to accomplish a communal tank with sterilized substrate if it makes you nervous.

4. PRIORITIZATION OF SPECIES
An approach I use that may be helpful for you is to prioritize a couple of “anchor species” of personal interest, and make my decisions for the tank based on their needs at the top of a hierarchy. Basically, I love millipedes most (the enclosure includes 16 individuals of multiple species, more on that below). Anything I perceive as a threat to them, I remove. Next priority are my 4 (males only, to avoid reproduction!) Halloween Hissing Cockroaches (Elliptorhina javanica), and 6 mixed-sex Harlequin Flower Beetles (Gymnetis caseyi). Everything else gets to stay only if these 3 main groups aren’t visibly stressed or disrupted.

5. SECONDARY SPECIES
Because I build substrate from the forest around my home, I’ve had some nice surprises. Interesting mushrooms that grow up and die off in a week, giving the springtails a nice feast. Craneflies that pop out and hang around for their short lives, feeding on apple slices and adding nice movement to the display. Animals I was initially uneasy about but have grown fond of are multiple species of harvestman. They aren’t especially large, and they’re fun to watch because they move a lot, and moult in the open. I’m coming to suspect they control populations of mites and possibly larval gnats. I haven’t witnessed them bothering any of my anchor species. At times they give exploratory attention to the millipedes, and I watch this very carefully because tactile overstimulation can stress them. However, I’ve seen them removing mites from millipede exoskeletons, and the interactions don’t last long. I don't observe any reaction from the millipedes, so I let the harvestmen stay. I’ve tossed in stink bugs and box elder bugs out of curiosity, and they haven't caused trouble – but they also aren’t especially interesting and easily escape.

6. HABITAT FEATURES
Early advice I received that has served the enclosure well is to provide as many places to hide as possible.The substrate is deep (somewhere between 8 and 9 inches) because there’s a lot of burrowing all the time. I want there to be lots of room under there, millipedes especially are at risk of being trampled by a clumsy cockroach or larval beetle (more on those below). I’ve also filled the enclosure with multiple chambers, hidey-holes, bark shelters, hollowed branches, and many climbing perches. Heavy objects compact the substrate, so I’m using curled pieces of lightweight bark, tubes of cholla, etc. Much of this is on the surface, but i also buried some in a section of substrate, creating underground cavern-like chambers and spaces. I want there to be as many places as possible for a creature to retreat to for alone time.

7. ATTENTION
I suspect my modest success so far is due in large part to my obsessive attention to everything going on in there. As far as I can tell, there hasn’t been a long history in the hobby of experimenting with species combinations and techniques for communal invertebrate enclosures (unlike keeping tropical fish, for which there is lots of knowledge available from generations of widespread trial and error). So i don’t think communal enclosures are well suited to people interested in following a list of criteria for set-up and checking in a couple times a week. This is nothing like setting up a Dubia roach colony and letting it run itself. I spend a lot of time sitting in front of the glass and just staring at what’s happening in there. I look in every time i walk by. I zip home from work over lunch to take a peek. I get up once (or twice!) a night to shine a flashlight around. I do paperwork and household tasks in view of the tank,  like some people work around TV with news or sports on. This is perfectly suited to my personality and interests, and it gives me a great deal of satisfaction. I feel this kind of close vigilance is necessary for the enclosure’s long-term sustainability, but obviously it's not for everyone. There are many variables to watch for, especially as natural lifespans run down or animals start reproducing.

8. MAINTENANCE
Maintenance is a little fussy. I keep a bit of supplemental food on the surface at all times: fresh organic veggies/fruit, dog kibble, and a cup of what i call “roach chow” (a ground mixture of rolled oats, wheat germ, and generic cornflakes). I have a metal screen lid, covered 3/4 with a sheet of clear plastic. I place a low wattage fluorescent tube fixture directly on the lid to add some heat and dry the climbing perches for my Orthoporus. I mist/sprinkle the surface every day (the light tends to dry the top of the substrate faster than I wish). Temperatures fluctuate because this winter has been cold, but a heat register sits directly below the enclosure’s stand (68 to 72 F, occasionally down to 65 or up to 76).

9. POTENTIAL TROUBLE

Here are a couple aspects that strike me as not ideal, or still concern me about the enclosure’s future…

--- Conflicting environmental needs... I have “desert millipedes” and “tropical millipedes” and “temperate millipedes” in this same enclosure. All but a small Apeuthes are native to North America, but I’m not confident I’ve figured out how to balance different habitat needs. The Orthoporus species seem happiest, and reward me for it. There are always several above ground, basking on perches or motoring around the surface. They do burrow, but for days not weeks, and with 12 individuals there’s always someone to see. Narceus also seem happy. There are 3 mature adults in there, and they surface only at night – but they show up regularly and I’ve observed them mating. I worry about the 3 Chicobolus spinigerus. They remain buried for long periods, and are never on the surface in daylight hours – and never for long. This doesn’t match published descriptions of their behavior. So what are they missing? Is the surface too dry? Does extra deep substrate have an over-cooling effect? Is a cryptic predator harassing them? I don't know. I haven’t seen the Apeuthes in about 12 weeks. Who knows what’s going on with that.

--- I may have put in too many beetles, and they may be reproducing too quickly.  Gymnetis caseyi adults are not bothersome to other creatures, they’re easy to satisfy with banana slices, and their larvae can be kept communally. I put 6 adults in; this has made the enclosure look interesting – they burrow more than I expected, but with 6 there are always a few visible. However, I didn’t expect them to reproduce so easily or so much. They must have begun laying eggs immediately, because I noticed larvae after 3 months. I’ve counted 8 against the glass at a time, this is likely a fraction of the total. I’m mostly worried about them disturbing millipede moults or eggs. I can’t dig them out (too risky for millies) so I think I'll remove adult females as they emerge, and keep females in an enclosure of their own for reproduction. 

--- How will I know when to replace the substrate? And how will i accomplish that? There’s a lot of substrate, but there are multiple species chewing through the sub at different rates. And much of this action is invisible to me. I suppose I’ll just plan on a schedule to set up a new tank with fresh substrate every year, and transfer everything from one tank to the other. But this strikes me as incredibly complex and time consuming. I suppose have 8 or so months to plan.

--- I expect that in the spring and summer I’ll be tempted to add additional animals I find around my yard and neighborhood. I believe there must be a limit, but i know I’m a boundary-pusher so I might make some bad choices. Starting a second communal enclosure for experimenting would be a smarter idea. But as people who do this understand, each new enclosure adds complexity to your life. It’s an adventure for sure

Reactions: Like 1 | Informative 3


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## Lithobius (Mar 28, 2018)

@davehuth that was very helpful, I'm planning to get a similar setup arranged in the next few weeks before too many things start hatching from the woods around my house, where I'm going to be sourcing my substrate also. I'm probably just going to flat out dig up some dirt as substrate as well. I just need to rehouse the Damon that's in the tank I want to use since I think the tank is too short for him anyway, not convinced he's got enough room to molt.

I've got a little isopod starter culture going thats a mix of different species (powder blue, dwarf white, powder orange) so I'd be interested in hearing other people's opinions in including isopods in these sorts of enclosures as clean up crew. They have to breed a little more before they're ready to go into any of my enclosures anyway.
My springtail culture is going well so I'm prepared there, if the isopods aren't going to work out.

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## LawnShrimp (Mar 29, 2018)

Isopods are voracious little punks. I love all of my cultures but don't trust them around any of my other inverts. A while back when I kept a large colony of A. vulgare, I also included small julids, polydesmids, and Abacion millis. Within a few weeks, the polydesmids produced egg masses and covered them with a wood-fiber dome. Not more than a day later, and each egg mass had been fully eaten by the isopods despite fish food chunks being readily available as protein. All of the adult millipedes were later eaten in their molts, as there was nothing in the tank but isopods.

While isopods may look cool, they are best cohabbed with vertebrates (that they can't harm) or things that don't come into contact with them, like mantids or phasmids. I suppose with enough hides and food one could keep them with beetles, but milllipedes are probably at a high risk.

Reactions: Agree 2


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## mickiem (Mar 29, 2018)

Totally agree with @LawnShrimp.  I love my ever growing collection of isopods, but I keep them by themselves or in vivs with frogs; never other invertebrates.  They are not team players and have never won the Miss Congeniality award.  But they are cute as all get out!  (How many of us loved a Roly Poly before any other bug??)

@davehuth I am diligent to sterilize everything in my species-specific breeding colonies and keep monocultures (except for springtails and predatory mites that find their way in). But I do have a few enclosures that I don't sterilize (not breeders per se).  I share your enthusiasm for the unexpected magic that happens there!  It always amazes me to see what appears.

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## Creobroter (Apr 3, 2018)

Abbio said:


> Hey! really happy to have found this thread as i have just created one myself but i haven't had any responses, be great to get this discussion going again.
> I cant seem to talk to anyone about this subject and i really want to learn from your exp before trying it myself!
> 
> What i wanted to put together was:
> ...


I see no reason why that wouldn't work; I've kept millipedes, isopods and springtails together with no issues. Fruit beetles should be equally harmless. Coco fibre should do as substrate. Maintenance is fairly minimal, spray the enclosure and provide fresh food, the springtails and woodlice will clean up most waste.


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## davehuth (Apr 30, 2018)

Just a quick update after another month of my fun experiment...

I think I need to do something about the beetles. I have Harlequin Flower Beetles (Gymnetis caseyi) and they are reproducing fast. I like that they're so easy-- they're awesome beetles, and play well with others. 

However, I had to do some maintenance which pulled up a chunk of substrate and I was a bit alarmed by just how many grubs are down there burrowing around. Dozens at the very least least. They aren't carnivorous or cannibalistic, but they move around a lot. My instincts tell me this is too much aggressive activity under the sub for baby millipedes or molting millipedes. 

I've pulled all the adults and set them up in a generous enclosure of their own, and whenever a grub gets close enough to the surface I pick it out. It will take a while to reduce the population overall, but I think it's best. Hopefully I'll get better at sexing these beetles so that i can put back in only males in the future, and do the breeding in the separate dedicated enclosure.

Live and learn!

Reactions: Like 1 | Agree 1


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## Abbio (May 9, 2018)

davehuth said:


> Hello @Creobroter and @Crowbawt , communal enclosures are in interest of mine and I was wondering how yours are coming along? I have had local Harvestman species appear in mine from unsterilized substrate, and I'm finding they add a lot of interesting visual and behavior appeal. I'd be interested in hearing about any issues/problems/unexpected delights in your communal enclosures (here or in a direct message). Thanks!


 Yes this is also what i was after from this thread!


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## Pocket dragon (Nov 18, 2019)

davehuth said:


> Just a quick update after another month of my fun experiment...
> 
> I think I need to do something about the beetles. I have Harlequin Flower Beetles (Gymnetis caseyi) and they are reproducing fast. I like that they're so easy-- they're awesome beetles, and play well with others.
> 
> ...



Do you have any more updates on how these projects turned out?


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## mossloft (Nov 19, 2019)

DubiaW said:


> Try setting up for some vertically inclined specimens. Small amblypygi wouldn't bother them. Maybe some small mantid species, jumping spiders, an ogre faced spider or _Centruroides gracilis _to take care of any flies that are attracted to the fruits and veggies you feed your millies. That way you have a little food web for pests and the like. I've never done something like this but I have been thinking about it. How about some _Blaptica gigantea_?


I've never thought of using arachnids and such in a communal tank- it would definitely make for an interesting setup!


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## donniedark0 (Nov 19, 2019)

Where did you acquire these beetles?




davehuth said:


> Just a quick update after another month of my fun experiment...
> 
> I think I need to do something about the beetles. I have Harlequin Flower Beetles (Gymnetis caseyi) and they are reproducing fast. I like that they're so easy-- they're awesome beetles, and play well with others.
> 
> ...


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## BepopCola (Nov 19, 2019)

mossloft said:


> I've never thought of using arachnids and such in a communal tank- it would definitely make for an interesting setup!


I like to add ornate harvestmen (Vonones ornata) to all my tanks, they're like a clean up crew and help control the little pests.

Reactions: Like 1


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