Being that we are making an aquatic ecosystem, you would think that a lot of attention should be paid to the water part of it. Fortunately, water is pretty simple.
How to treat your water
You have two options. The first option is to create neutral water and use it to fill your jar. Neutral water is the same stuff you fill up a fish tank with. You can buy water conditioner online or in a pet store pretty cheap. Mix the tap water and the neutralizer in another container, and then pour the water into your jar after you’ve waited the requisite time. If you don’t want to purchase a neutralizer, you can fill a vessel with tap water and leave it out for a couple days. This will have the same effect, albeit to a lesser degree. For a jarrarium though, you can probably get away with it. The inhabitants of jarrariums are not so sensitive as those found in aquariums.
The second option is to use pond water. Go to your nearest body of freshwater and fill up a bucket. Get water from the edge of pond, rather than the middle. The deep part of the pond will have a slightly different composition of microorganisms than the edge. You want the kind that live in shallow water, because your jar is shallow!
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Try to avoid catching clumps algae and other hitchhikers like snails, bugs or fish. What you’re trying to capture is the microorganisms that live in the water column of a pond. It will be a mixture of phytoplankton and zooplankton. They are integral to the health of the pond, and they will be important to your jar as well. Don’t worry if you can’t see anything; these organisms are virtually omnipresent in all water – you’ll get some.
In most cases, you will want some small amount of pond water to start your jar. It helps to establish a healthy ecosystem by introducing elements that won’t be present in tap water: bacteria and microorganisms. If you are going for that clean, elegant artistic jar you can omit the pond water. It will inevitably carry algae that will mar your piece. Simply use neutral water in that case.
Additional notes about water
In your jar, you will want to fill the water up to an inch from the surface. It’s important to leave some space there, whether or not your jar is filled, for gas exchange. Air moves from in the water to out of it, and vice versa. If you didn’t leave space, it could suffocate your plants and animals in the jar. Another reason to leave space is snails. Particularly adventurous gastropods sometimes venture out of the water and into the air. They’re not always smart enough to find their way back, though, so if your jar is unsealed they might wander off and dry up. No one wants to find an empty snail shell on their counter. If you leave space between the water and the rim, they are likely to stay in the jar.
Don’t worry if your water is cloudy or dirty when setting up your jar. This is common. The sediment will settle out of the water within a couple of days and your jar will become clear again. It won’t harm the plants or animals inside as long as it doesn’t last for several consecutive days.
Now that you’ve sorted out the water, you need to cycle it. Here’s all you need to know about cycling.
Hey Patrick, great site! I’ve been trying to absorb a ton of great info on here. Since I can’t have an aquarium at work, a jarrarium is the next best thing.
Quick question: there aren’t many ponds around me. I live and work in the ‘burbs. I am near a marsh… would that water work? How about lake water? There is a pond here but it’s part of a business park… I would imagine that would not have the same affect as a pond out in nature? And I’d imagine it might have other stuff in it I wouldn’t want in a jarraium (additives/chemicals)? Though I do see plants growing in it.
Would love any advice on this. Thanks!
Any of your proposed bodies of water would suit a jarrarium just fine. They all have different species assemblages, put there is enough overlap that it would work either way.
Even the pond in a business park has all of the necessary microorganisms, but I wouldn’t use too much water from there. It probably has road runoff and fertilizer runoff which aren’t desirable.
i have this crazy clear fish bug looking thing that appeared out of no where! it’s about an inch long. it almost looks like a dragonfly with fins! but it’s transparent! if you might know what it is i can send you a video because i really want to know what this thing could be.
That sounds pretty interesting! It might be a dragonfly or a mayfly nymph. If you upload the video to Youtube or something, then send me a link through the contact form I’ll take a look.
I’ve just recently made my first self sustaining ecosystem about 2 weeks ago. I haven’t seen any movement in the jar yet. How long does it typically take? I’m so impatient lol! I also added a ghost shrimp but I looked a week later and he is dead. Am I doing something wrong?
Look more closely, there are probably already lots of very tiny organisms moving around.
I can’t advise on what happened to your ghost shrimp without information on water parameters.
So I decided to try this! I went to my pond and scooped up some water. I can already see lots of little creatures along with what I think are two tadpoles. I didn’t get much sediment, should I go back out and try to get some? Also do I have to feed the creatures? And should my jararium be in the sun?
Tadpoles are vertebrates, so they need more maintenance than most of the critters in your jar. I would recommend releasing them. You shouldn’t have to feed the inhabitants of your jar, they will eat algae and “infusoria”.
All your questions are answered in other jararium posts here on the site – keep readin!
Hello! Thank you so much for these articles they are incredibly helpful! I was thinking of making my own ecosystem but I don’t have access to any ponds, only small streams. What are your thoughts on using running water because I have seen a couple of things online saying it’s not a good idea to use for an ecosystem?
Hey Anna. It’s not ideal since the organisms you’ll end up with are adapted to a riparian environment, not a lentic one (ponds or lakes). That said, there’s plenty of overlap between the communities so the jar should still have plenty of life!
hi! so i live in a desert which means there is very little pond / lake water near me at all. i was wondering if a park that has a lake would suffice for obtaining those bacteria and micro organisms – ducks + turtles live in it.
thank you!
Any lake or pond will work 🙂
Not sure if you still read these, but your guide led me to create a very successful 2 gallon jarrarium that is going on 3 years. Thank you, I couldn’t have done it without all of your info.
I’m really glad it helped you CG 🙂
I live near a spring that is pretty cold year-round (~68F). Would i still be able to use that water even if the jarrarium would be warmer than that? All of your articles have been so helpful, thank you!
That is a good question! You can certainly still use that water, but you’ll have less action in your jar for two reasons:
1. The temperature, like you said, will be significantly different in your home and may not be suitable for all the critters.
2. The source of a spring is usually less diverse than the same body of water further downstream.
Hi, I’m so glad to see that you’re still replying to comments! I’ve enjoyed reading your content and have a one gallon jarrarium of my own. We’re going on four months!
Early on, I noticed a small creature that has since transformed into a dragonfly nymph! Although it is an invertebrate, it is predatory and has become a bit large.
I wonder how long its lifecycle will be considering that it won’t be able to fully mature.
Thoughts? Advice?
I’m too busy with graduate studies (in closed ecological systems!!!) to do a lot of blogging these days, but I still love chatting with people in the comments here 🙂
Dragonfly nymphs are the terrors of natural jarrariums everywhere! They are voracious, so cool to see them hunt. If you keep enough food in there they can make it all the way to maturity in a jar, but a lot of them hunt vertebrate prey (fish/tadpoles) as they get bigger.
I usually let them go when I spot them.