Here comes the fun part…
Finally, the section we’ve all been waiting for! Animals are probably what inspired you to this project. There’s nothing more fascinating than watching a minute copepod flit around in a jar or a snail crawl up the glass sucking in invisible algae. You wanted to find out what goes on underwater, and here’s your chance. You’ll spy invertebrates you didn’t know existed; like isopods trundling slowly but surely over debris. After a couple of weeks, you’ll notice a network of tiny tunnels in the mud next to the glass. You might even see a resident polychaete worm sticking its head out of the tunnel fishing for plankton. If you pulled any substrate or plants from a pond, you’ll almost inevitably find tiny little snails in your jar after a few days.
What kinds of animals can we choose from?
Before we get too far ahead of ourselves, let’s go over some lingo so we are all on the same page. I keep using the word “invertebrate.” What does that mean? Literally it means “has no vertebrae”. An invertebrate has no spine (or notochord, but that’s some developmental biology we don’t need to get into). Thinking about it, there are lots of animals that lack a spine: jellyfish, the octopus, bugs and spiders, snails and slugs, crabs and lobsters, etc. Then, of course, we have the vertebrates: humans, other mammals, birds, fish, reptiles, amphibians, and more.
I don’t like to generalize, but invertebrates tend to be biologically “simpler” than vertebrates. Sometimes it means that they have fewer requirements to live healthily. It might mean that, physiologically, their bodies are not very complex. Often times, they’re relatively dumb (why won’t moths stop flying into porch lights??). However, what invertebrate means to us as jarrariumers (jarrarists?) is “easy”.
See, a snail (invertebrate) doesn’t really mind being in a container the size of a peanut butter jar. Maybe it’s too dumb, or maybe it has transcended our petty, materialistic desires and has found nirvana in its minimalism. But if that snail has some chow, can breathe, and has enough room to turn around – it will be happy.
A betta fish (vertebrate), on the other hand, does not share the same satisfaction in such a jar. The typical betta container, those tiny 10 oz. cups, is one of the greatest sins of the aquaria trade. Betta fish are remarkable in that they can survive in such a small amount of water, without aeration, heat, food, for such a long time. Naturally, we have exploited them for this wondrous adaptation and that is why you see them stacked on top of each other on a Walmart shelf.
Why shouldn’t we use vertebrates?
”Bioload” is what we call an organism’s impact on the environment. The term encompasses the necessary food, gases (like oxygen), and waste of the organism. It places emphasis on the waste they produce because that can have a direct negative effect on its neighbors. Small containers have a lower bioload capacity, and vertebrates always produce many times the bioload of an invertebrate of equal size. The relative complexity of a vertebrate’s life systems, like digestion and waste, are usually more inefficient and end up producing a higher quantity and more potent wastes.
See, there is really no vertebrate that does well in tiny spaces. Even if you gave them everything technically required for life, the simple lack of space would stress them out. If preventing stress isn’t motivation enough for you, prolonged stress in animals often causes illnesses or early death (that goes for people too!). Because of this, you should not have any vertebrate in a jarrarium. Correct, that means you can’t have fish. Not even small ones. There is simply not enough space in a one or two-gallon container to provide a happy environment for any vertebrate, so I can’t condone their usage.
List of Beginner Animals
Don’t despair – there are plenty of invertebrates that are equally as interesting as fish. Note that when deciding to purchase snails, you’ll need to be aware of their reproductive habits or your jar will be overrun. Likewise, shrimp (another common jarrarium buddy) have a couple of special rules. Most shrimp are social creatures, and are much healthier and happier with another of their species. But shrimp also require space. You should ideally have one shrimp per gallon of water, but definitely no more than 2-3. Without further ado, we’ll go over some exciting candidates for your jar’s animal population.
Pond Snails (Lymnaeidae genus)
Pond snails are a pest when they spontaneously appear in aquariums or fish store tanks, but in jarrariums they are a welcome guest. They help clean up algae that grows on the glass or on your plants. They’ll motor around the jar, vacuuming up debris and leaving the environment cleaner than they found it. That’s what I call civil service.
They are hermaphrodites, like many snails, meaning they are simultaneously male and female. Most pond snails can even fertilize themselves. You will undoubtedly find snails eggs on the glass or spy them on a leaf at some point. The bunch of eggs will appear as 6-10 transparent dots encases in an equally transparent film. If you find that your snail population is exploding, it is because there is too much food. If you’re feeding the inhabitants of your jars, you need to cut down on the amount. The population of snails will eventually stabilize, although they may munch on your plants.
There are lots of species of Lymnaeidae all over the world. If you pull plants from a pond or use pond mud, you will certainly accidentally also get snails eggs. If you order plants or animals from a breeder, you will probably also get snail eggs unless they go to great lengths to avoid it. Don’t worry about it though, these guys are pretty cool. Watch them float upside down on the surface using an invisible band of mucus, or their circular, spiky tongue called a “radula” continuously scraping the glass for food.
There’s really no point in buying them online. Just go scoop a bit of mud out of a pond, put it in a jar, then wait a couple weeks. These guys will show up, guaranteed.
Nerite Snails (Neritina genus)
These are the big snails you see at fish stores. They come in a variety of colors – golden, opal, zebra striped, and everything in between. These snails are pretty big too, often almost an inch long when full grown. Nerites are very hardy and will adapt to any reasonable water conditions.
One of the great things about nerites is that they require brackish water to reproduce. This means that you won’t have any problems keeping their population in check! This is fortunate for us, because the large size of nerites means that they have a significant bioload. You shouldn’t have more than a couple per gallon of water.
Nerites also fall in the “tank cleaner” category. They looove eating algae. All different kinds too! Some nerites burrow under the substrate and eat that hard-to-get brown algae. Others will scour the surface of your substrate, while yet others roam the glass. They tend to avoid eating plants, which makes them great additions to ornamental jarrariums.
You can usually find some ordinary nerites at pet stores or on Amazon. If you’re willing to pay a little extra, you can get some really cool-looking nerites elsewhere.
Ramshorn Snails (Planorbidae genus)
These snails have a very distinguished spiral shell that is so characteristic to our ideal snail. They also come in several colors, and can be quite pretty to watch. When they’re young, their shells are transparent. Ramshorns are common at pet stores, and usually a bit cheaper than nerites.
Ramshorns, however, are quite prolific. If there is more than one Ramshorn in a jar they will breed. Ordered plants from online or a pet store may also come with ramshorn hitchhikers. Their eggs are found in clutches of clear goop. You’ll easily find them when they appear on the glass, but good luck finding the dozens more hidden in the jar.
They tend to be more active than nerite snails as well. They move faster and like to climb on plants and other decorations. Be warned: they will eat plants. They are normally content to feed on dead plant matter or shed carapaces of invertebrates, but if you have a soft plant they will take a bite. Hardier plants usually escape unscathed.
I like to keep both a ramshorn and a nerite in a jar – it adds variety and prevents snail breeding so your bioload remains low.
Grab your ramshorn at a local fish store or grab them on Amazon here.
Ghost Shrimp (Palaemonetes paludosus)
Ghost Shrimp, sometimes called Glass or Grass Shrimp, are the perfect addition to any beginner jarrarium. They are ultra-cheap at aquarium and pet stores, and very low-maintenance. They are omnivores, so they’ll nibble on plants, algae, and detritus. Ghost Shrimp don’t hunt, per say, but have been known to eat their own larvae if they don’t have abundant food. You should rarely need to feed them directly in a crowded, lively jar.
These shrimps are very fragile, and thus, peaceful. They sometimes suffer in tanks with fish, as fish like to nibble at them. In order to make your Ghost Shrimp happy, make sure they have a couple of places to hide. The inside of shells, rocks, or dense tangles of driftwood are perfect refuge for them.
Ghost Shrimp are especially fun because they can turn a jarrarium into a game of hide-and-seek. It’s tough to spot the transparent little guys, especially before they’ve grown to adulthood at 1-2 inches. You can even identify different individuals, as they will often have a colored spot above their tail.
These are very common freshwater shrimp. You can find them at any decent PetCo/PetSmart. If they’re not in stock, just grab some off Amazon.
Amano Shrimp (Caridina multidentata)
The Amano hails from Japan and fits in well in all kinds of jars and aquariums. It often has dark polka dots in lateral lines with a base color of tan or yellow. Amanos can thrive in a nice, clean, organized jarrarium, but it really shines in a messy one.
This shrimp is something of a legend amongst aquarists for its supernatural cleaning powers. The Amano Shrimp is probably the single best tank-cleaner in the world. This crustacean moves its little pinchers unceasingly in an effort to pick up every last bit of muck, algae, or dead plant in its environment. All it wants is for you to be proud of it.
These are very active, friendly shrimp. In the absence of predators, it almost never stops moving. They’re quite entertaining to watch puttering around, scooping up handfuls of food and putting it in their mouth. Ensure they have an ample supply of algae, fish food, or plant matter to munch on.
Want to buy Amano Shrimp for a jarrarium? You can get them at this link!
Cherry Shrimp (Neocaridina davidi)
The Cherry Shrimp are the crown jewels of the aquaria trade. Most often found in the red variety, they are known for vivid coloring. The intensity of that color is actually measured in grades, with brighter red shrimp being more expensive than paler shades.
Cherry Shrimp are at home in a generally broad range of conditions: pH of 6.5-7, temperature around 70°F, etc. They like to sit on live plants while they graze on the biofilm of algae that grows on their surface. These shrimp will rarely, if ever, munch on plants, so make sure they have ample food from detritus or fish flakes.
The coloring of these shrimp provides great contrast with the typical dark greens of a planted jarrarium. If aesthetics is your goal, red Cherry Shrimp should be a tool. A small group of 3 is easily maintained in a jar of at least a gallon, and their bright colors will draw the eye to perceive small details in their surroundings.
These are fairly popular shrimp. You should be able to source them from other aquarists or a particularly nice fish store. Otherwise, buy red cherry shrimp online! That’s a link to our favorite place to go shrimp shopping.
If you choose to utilize pond mud and pond water, you will have a whole host of animals you may or may not be able to see. There are many thousands of creatures that exist just out of sight, either because of size or because of habits. For example, you might see miniscule, thread-like worms sticking up a couple centimeters out of the mud. Those are probably polychaetes, commonly called bristle worms. Even if you don’t see them directly, you’ll certainly find their network of small tunnels pressed up against the glass.
There are many microinvertebrates you will never see with the naked eye. If you took a drop of water from your jarrarium and put it under any old microscope, though, you would find loads of them. There are a few microinvertebrates that are on the edge of being visible, namely copepods and daphnia. These arthropods are noticeable as tiny specks that flit around in the water, eating algae or other microorganisms. You won’t notice them at a glance, but if you look closely at the debris on the bottom or near algae you’re sure to find them.
Even larger are the amphipods and isopods which are almost sure to show up eventually. These are a kind of crustacean, like shrimp, but they look just like a roly poly (or pill bug, which is also a crustacean). These are important detritivores in aquatic systems; they eat dead stuff that builds up on the bottom, recycling it into energy. Make an effort to capture a couple if you see them, otherwise you can depend on the fact that there will probably be eggs in the mud you grabbed. You can tell the difference between isopods and amphipods in their method of locomotion: amphipods swim on their sides and isopods walk along the bottom.
After animals is creating your style: How to Aquascape.
Wondering if in a mud pond type substrate , could you still include shrimp? also can you have a combo of shrimp together say cherry with amano?
Good question. You can definitely still include shrimp in a pond-mud based jarrarium, but you would need to monitor the chemicals closely. There’s more variation in chemical balance (at least initially) when you just transplant a portion of an ecosystem.
There’s also a small chance that the mud might carry parasites, but it’s very unlikely so I wouldn’t worry about.
Yes, you can mix different types of shrimp! None of these microshrimp are aggressive.
Hows a worm for a jarrarium? What will I need to do to keep it alive for 3 weeks?
For an aquatic jarrarium? None of the worms you find in the dirt will survive very long. There are loads of aquatic worms, though, and if you scoop some mud out of a body of water you’ll definitely get some. They tend to be very, very small though.
Is there a way to seal a Jar with Shrimp and make them completely self sustaining or do i have to reopen the Jar and feed them from time to time? If so, which shrimp are suitable for such a Jar? Thank you for your help!
Generally speaking, when you have animals in a jar, it’s best to keep the jar open so that gas exchange can occur at the surface of the water. It’s technically possible to do without, assuming you have lots and lots of plants.
The best shrimp for this would be either ghost shrimp or amano shrimp.
I know you’re able to put various snails in, with that said am I able to place a slug in mine?
Well, jarrariums are aquatic so terrestrial snails or slugs can’t survive in a jarrarium. There are freshwater snails, but no freshwater slugs.
I have started a gallon Mason jar with a few moss balls and plants from a canal in south Florida. Sediment and water from the canal also. I topped the sediment with the store gravel. I had a few creatures from the canal and very tiny snails. I bought 3 from the store and all have been doing well. I added 3 ghost shrimp and they died within a couple of days. I had the water tested and the ammonia was high. I added some treatment and tried 2 shrimp again. They lasted 2 days. Should I wait awhile for my jar to settle and let the snails balance everything out for awhile then try the shrimp again? I really want it to work out. It’s beautiful and clear. The plants are doing well also.
It takes a few weeks for the system to “cycle” – to establish a functioning nitrogen cycle with the microorganisms in the sediment. Until then, the system won’t be able to process the ammonia into less toxic nitrate. You should hold off for a few weeks before adding shrimp (and test the water first).
Is there any other animals other than snails and shrimp that u can actually see that can coexist with shrimp and snails that can live in a self sustaining
That’s a good question. There aren’t a lot of “charismatic” species that fit that bill. You could try going out of the box a little bit and keeping something like Triops. I’ve heard of people keeping various types of water insects like “backswimmers” or “toebiters”, but most of those are aggressive.
Honestly, my suggestion is to become interested in plants! I get just as much out of the plants in my jar as the animals 🙂
I’m very new to the jar world. I just closed a freshwater, pond/mud, 1+ gallon jar 3 days ago. It’s already starting to settle nicely. I’m beginning to see all sorts of life ((larvae, bugs, multiple snails, worms, eggs, etc.)), but I have not reopened the jar. I’ve been reading around && it seems that if there is enough space left at the top of the jar ((for gas exchange)), you do not have to reopen it. Is this incorrect? Do I need to be opening my jar? If so, how often?
Well, sure, gas exchange will occur at the surface… but you’ve sealed in a finite amount of oxygen. Once that is consumed you’re not going to generate any more in a sealed jar (without lots and lots of plants or algae)
Hi Patrick, I am starting a closed off ecosystem for an environmental class project. You seem to know what you’re talking about, and I was wondering what kind of ecosystem I should make to have the best results?
Thanks for the info!
I’ve got a closed, unheated jar with an Anubis, one Malaysian trumpet snail, and a few ramshorns. It’s been a year or so and everything seems to be ok. I just started to put a little more effort into partial sunlight to encourage algae growth
As long as I have the jar vented, I could put in ghost shrimp?
Water temp is around 70 degrees.
If your system has been stable for so long, I’d be a little reluctant to mess with it. Whether or not it can support additional bioload is dependent on the volume of the jar.
But, yeah, chances are you could squeeze in a ghost shrimp or two. They’re very hardy.
I have a fresh water clam in my ecosphere, seems to be doing ok? have anyone put a clam in theres before. Will it survive?
Unfortunately, clams are generally a bad choice for jarrariums. They filter water very rapidly – depending on the species, they can go through 10 gallons or more a day. Your clam will quickly eat all of the available plankton and other microorganisms and starve to death, so it might be a good idea to release him again.
I had a very lively jarrarium for about a week and now everything seems to be dead… we saw several micro fawna, snails, worms etc. I do know we had a small crustacean but unsure what kind he was. The worms look white now and nothing is swimming. I airred the jar everyday. Any advice? All creatures were from a mud pond next to my house.
Hmm, it’s hard to say without more info, but it sounds like they all died because of temperature swing.
I just started one today (from a river with a rocky bed) I have noticed a few things swimming around already and have seen a snail do I need to feed them anything since I just started it out?
No need to feed them! They’ll eat algae and infusoria, and the population would eventually change to match the amount of food available
How many shrimp are recommended for a 2 gallon ecosystem
Hey Nlamh – my apologies for the late response. The general rule of thumb to follow is 2-5 shrimp per gallon. Do note though, that certain species of shrimp do better in a more or less crowded environment. Additionally, the size of your shrimp population isn’t entirely in your control, so it’s better to be safe than sorry. I’d lean towards the lower end of the spectrum – 2 or 3 shrimp – and watch how your population levels react before adding more.
Is it a good idea to make a jarrarium during late fall (now? I live in South Jersey)
Hello, can I make a jarrarium during late fall? I live in the S Jersey pinelands
Of course! Many microorganisms go into a type of stasis, like hibernation, when it gets cold. Once indoors and warmed up, you should see activity from small copepods and the like.
Thanks so much I’ll keep you posted!!!
Hi! I am looking to start a pretty clean/ simple jar with shrimp and moss. Preferably sealed.What is the best way to go about this? Do I need other plants or will the moss be enough? should I feed the shrimp/what do they eat?
I wanted to make a small Mason jar sized one for on a desk. I’m seeing most people do a gallon. Is a small jar okay? I have hundreds of trumpet snails and was hoping to make a bunch of Mason jar ones with Java moss for kids.
It’s considered a bit inhumane to keep most inverts in mason jar-sized containers. They would probably survive for a while, but there’s not enough water to buffer temperature or chemical changes so it won’t be a stable environment.
Hi Patrick Grubbs, I am starting a closed off ecosystem for an environmental class project. You seem to know what you’re talking about, and I was wondering what kind of ecosystem I should make to have the best results?
Please Email me at firstname.lastname@example.org
I guess it depends on how you define “best results”. The simplest method is to simply throw mud, water, and plants from a local pond into a jar. Those usually turn out pretty diverse (good for class), if not very beautiful.
would you need a bubbler for the ghost shrimps?
Invertebrates don’t require as much dissolved oxygen in the water as vertebrates like fish, so it’s not necessary. That said, they do appreciate water flow and it would probably make them happier.
Hi Patrick, i just started the ecosphere thing a couple of days ago. I’m seeing quite a few snails, amphipods, n worms swimming around. Im wondering if i can and shud introduce some predators or creatures at the top of the food chain to prevent overpopulation in the future. Do you have any suggestions?
That’s a great question! The answer is pretty easy: nope.
Overpopulation in a closed system is very rarely a problem. There’s a finite amount of resources in your jar which sets a hard limit on the number of organisms the jar can support. The populations will go through boom and bust cycles, as populations do at every scale – it’s called dynamic equilibrium. There’s very little chance any population would go extinct if the system remained stable, though that’s not realistic either – your jar’s conditions will change over time because the volume is too small to effectively buffer that change.
Certainly there are already tiny predators in there – they will likely die eventually. Adding more trophic levels to a system vastly increases its complexity and the likelihood that it will collapse. Most long-term jarrariums only have primary producers (plants/algae) and grazers (herbivores).
Hi, I’m hoping to make an ecosystem in my 10g tank with filter that is as self sustaining as possible, so no-very few water changes and feedings. I will use marino moss ball, java fern, java moss, anubias, and floaters like frogbit and red root floaters.
I was hoping to add at least 1 mystery snail, 1-2 nerite snail, 1-2 amano shrimp. There will undoubtedly be some hitchikers on the plants as well.
Do you have any advise for me on how to make this a nice balanced ecosystem?
Different stocking ideas? I was thinking at some point adding 2-3 african dwarf frogs and a food species like bloodworms and daphnea would be nice?
If I added a few cherrie shrimp, would I need something that eats them/the babies to keep population in check? What would be some options?
Let me know what you think!
That sounds like a lovely aquarium 🙂
It’s worth noting that, if you put vertebrates like frogs in your system, it’s going to require more maintenance. Also keep in mind that bloodworms and daphnia won’t create a self-sustaining population just by existing, they have to be cultured/bred.
Shrimp populations are typically self-governed by how much food is available. I’m pretty sure the frogs would eat small shrimp anyway, so there’s no fear of population getting out of control.
What creatures are good detrivores that help break down the snail and shrimp poop?
That’s done by denitrifying bacteria and other microorganisms that naturally “show up” once a system has been thoroughly cycled.
Hi, I am doing a closed biosphere project for my environmental class and I don’t know what animals would survive. What terrestrial animals would be good for a closed biosphere, I’m thinking a snail or ghost shrimp?
There aren’t any terrestrial shrimp (though I suppose cockroaches are pretty close). A small garden snail might work. Terrestrial jarrariums (terrariums, you might call them) typically only support microorganisms like springtails and pillbugs/woodlice/sowbug/rolly-polly.
Our project has both terrestrial animals and plants and aquatic. So would a garden snail for the terrestrial part work? I would have another water part for the shrimp but I just don’t know if it would stay alive because it’s closed.
Their survival depends on how large the system is and the environmental parameters. I assume since the system is closed, it’s probably a smaller jar. Neither a snail nor shrimp will survive indefinitely, but either could probably last for the duration of a school project (less than a month or so?). If you really want to go for longevity, I’d actually recommend springtails/pillbugs on land and aquatic pond/bladder snails (which you can find in any pond or creek).
I have an open jar with a few snails, moss etc that has been set up about 5 months. Today I saw a barely visible creature that looks a bit like a starfish (in that it has 5 delicate tendrils). It was just suspended in the water column but had some movement. What could this be?
I tried to take a picture but my phone wouldn’t focus on it
It sounds like you found a Cnidarian (some animal in the jellyfish family). It’s extremely unlikely to be a freshwater jellyfish, so it’s more likely that it was a hydra (a common freshwater pest). They typically anchor themselves to substrate (look closely on the glass and you’ll likely find more), but sometimes they detach and move.
I’m planning to create a closed 1-gallon terrarium in a jar. With pebbles and a little charcoal as a drainage (deepest) level, forest gathered soil in a medium level and also natural moss, lichens and other small forest floor plants/herbs. I’m also going to add a decayed piece of wood, some dead leaves and most importantly some worms. And here is my concern – will couple of redworms, woodlice, 1-2 forest snails, 2-3 centipedes and springtails. Will these have a chance to coexist and reproduce in a closed ecosphere? As for springtails – is it a chance of getting them as hitchhikers in a forest floor (in Poland)? Or do I have to buy them? And is it possible to create the terrarium now in the middle of autumn?
I’m looking forward to hearing from you,
Realistically, there’s simply not enough space in a 1 gallon jar to contain a self-perpetuating detritivore ecosystem you have described… but it may last a good, long while – which is a fine achievement. It’s likely that your centipedes will eat many of the other inhabitants before a breeding population is established, so I’d recommend omitting them. The rest of your suggestions are good! You will definitely get some springtails as hitchhikers, but whether it creates a sustainable population is another story. You may have to cultivate or buy them. Season shouldn’t matter too much, any dormant critters will wake up when the jar is warmed indoors.