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.
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.