Both a challenge and a delight, creation of a 20cm nano aquascape triggers such an urge inside one. I’m firm in saying that inspires creativity, precision, an eye on detail into the making of a beauty, being an aquascaper for years. However, this is where the magic happens of turning what basically seems to be an impossibly small canvas into a thriving, balanced ecosystem. The thing is, people often say to me, “But it’s only 20cm; how can you really do anything with that?”-but my response to such is always the same: The limitations are what make it so rewarding.
Working in small scale means every decision counts. Each rock, every plant, and every fish must have its own purpose, which then again is the reason why nano aquascaping is a real test of skill. That is embracing simplicity while making the most out of the limited real estate. In one way, it’s like forcing the painter to work on a mini-canvas, whereby you are forced to focus on the core of your vision and leave out all that unnecessary trivia.
I can still remember my first try at a 20cm nano aquascape, which was a disaster. I’d packed as many elements as possible into the tank, thinking that somehow I would be able to create that grandeur of a larger aquascape. All I ended up with was a chaotic mess. But it was a good lesson learned the hard way: With nano tanks, less is always more. Ever since then, I have done the minimalistic approach. It doesn’t mean the aquascape is uninteresting or not deep; rather, I started becoming more choosy about what goes into it.
One of the first things I tell people new to nano aquascaping is: planning plays a big role. In larger tanks, one has space to experiment, but on a 20cm tank, there is little room for error.
One wrongly placed stone or overgrown plant completely overflows into the space. For this reason, I always start off with a rough sketch or digital mockup even before commencing with aquascaping. By visualizing the layout, I am able to anticipate possible shortcomings and allow me to plan the flow and balance of the aquascape.
Balancing Simplicity and Detail One of the biggest problems while working in a 20cm tank is trying to find that delicate balance between simplicity and detail. It is so easy to go too far one direction or another, either becoming too barren and boring or getting overly crowded and cluttered. A trick I have found effective is focusing on a single focal point.
That could be some striking piece of driftwood, a well-positioned stone, or perhaps even a standout plant species. With these kinds of anchors for your eye to hold onto, you could then lavish the rest of the aquascape on that focal point, making it cohesive and visually appealing.
On one of my more recent projects, I used a single, gnarly piece of Manzanita driftwood as the centerpiece.
Its natural, twisted form caught the eye right away and set the pace for the rest of the tank. I placed smaller, rounded stones around it to counteract the sharp lines of the driftwood and planted Bucephalandra and Anubias nana petite to provide unobtrusive greenery that did not overpower the space. The result was an aquascape which felt balanced yet detailed, even in such confined space.
I’ve also learned to love negative space. Sometimes, just leaving areas of substrate or water open can make a tank feel so much larger than it actually is. I’ve had friends come over and remark on how spacious my 20cm tank looks, even though it is one of the smallest aquascapes I’ve done to date. Negative space helps create depth, and gives the eye some room to breathe, which is so integral in such a small environment.
Selecting the Right Plants, Hardscape, and Inhabitants for a Nano Aquascape
Once you have designed your layout, it’s time to think of the plants, hardscape, and denizens. In a nano aquascape 20cm in size, everything needs to be well thought out. The scale is such that one ill-placed or too-large plant or a misplaced rock may completely throw the overall composition out of kilter. Here’s where experience plays a major role: over time you develop a feel for which types of materials work in such a small space and which do not.
Choosing the Best Plants
The best way to succeed in the nano aquascape is by using plants that tend to be small and do not grow at all like they used to, thus requiring constant trimming. I made this mistake once by using fast-growing plants like Rotala rotundifolia in small tanks. They look fantastic while in the first week or two, but in weeks, they overgrow the tank, and there is constant maintenance awaiting. In a 20-cm nano tank, this gets frustrating very fast. So slow-growing, low-maintenance plants work best.
Some of the following plants have become my go-to species for 20cm nano aquascapes.
Anubias Nana Petite: A dwarf variety of the popular Anubias species that does well in nano tanks. It grows only to a small size, attaching well to rocks or driftwood, adding a touch of lush green without becoming overwhelming in the tank.
Bucephalandra sp.: A type of slow-growing plant which generally comes in different forms and colors. This is a modestly beautiful plant, which could be applied to add some texture to your nano aquascape. Marsilea hirsuta: If your goal is a carpeting plant, Marsilea hirsuta is generally a very good choice. This plant doesn’t grow too tall, and with little effort, it’s able to form a respectable dense carpet. Cryptocoryne parva: One of the smallest species of crypt, it also tends to grow quite slow and is perfect for nano tanks. I use it quite often in the foreground to add some different leaf shapes and various size variations.
Java Moss: Moss added onto a nano aquascape is always great, since it can soften the hardscape or just make the aquascape look more natural. It is easy to care for and grows slowly-what’s important in such a small tank. One trick I have learned over the years is to think of the placement of plants in layers. You don’t have much vertical space in a 20cm tank, so the idea is to create depth with careful placement of plants. I put taller ones, such as Cryptocoryne or Sagittaria subulata, in the background, placing most of the smaller species in the midground and foreground so that things scale better.
Hardscape Choices: Rocks, Wood, and Layout
In nano aquascaping, of course, the hardscape really leads the show. Given the tank is so minute, the rocks and the driftwood you choose are going to define the structure and feel of the aquascape as a whole. Over time, I came to really like Seiryu stone – it’s really rugged in texture, with deep crevices and all that.
Seiryu stone provides dramatic, striking contrast with more delicate plants, such as moss or Bucephalandra, so the crevices could be tucked into for a natural-looking integrated stone.
But one of the most important lessons I have learned on this nano tank is that it is so easy to overdue it with hardscape and where on a 20cm aquascape you simply don’t need a massive pile of rocks and an immense piece of driftwood to create impact.
Instead, a few well-placed elements can go a long way. I once tried to replicate an Iwagumi-style layout in a nano tank using multiple stones, and the result was far too cluttered. After scaling back to just three key stones, the composition felt much more balanced, and that field of view had calmness and openness that was missing before.
I also like to use Manzanita driftwood in nano tanks. The subtle, branching structure contributes a light, almost airy quality to the aquascape that prevents the layout from feeling heavy or crowded. One of my favorite techniques involves placing a small piece of driftwood so that it carries the viewer’s eye upward, creating vertical space in a tank only 20cm tall. With low-growing plants, this trick can make a nano aquascape feel a lot larger than it actually is.
Inhabitants: Fish, Shrimp, and Snails Properly choosing the nano aquascape inhabitants is just as important as choosing the plants and hardscape. You must be extremely selective about what you put inside a 20cm tank. You can’t simply fill up a small tank with too many fish, for this can create a lot of water quality problems besides stressing the ecosystem. That’s why I usually recommend going with shrimp or small snails as primary inhabitants when it comes to a nano tank. One of the prettier shrimp species for a 20cm tank would have to be the Cherry shrimp, Neocaridina davidi.
They remain fast-swimming, colourful, and fairly easy to care for. They help clean up algae and detritus immensely, which really helps in keeping the tank looking pretty clean. Their small size doesn’t hurt, either, since they fit so easily into such cramped quarters.
Another excellent choice is Amano shrimp: Caridina multidentata. They are a little bigger than Cherry shrimp, but fantastic for cleaning algae and rather entertaining to watch. For that matter, it is somewhat amusing to watch a group of Amano shrimp cleaning a small patch of algae!
While choosing the fish, it is a must that the species be indicated to remain small and barely in need of a swimming space area to swim. In any nano tank, my go-to options include the ember tetras or Chili rasboras. These are very small, peaceful fishes which will give a dash of color without overloading the tank. Just be sure not to keep more than 4-5 in a small tank this tin. Lastly, I always add in a few Nerite snails to the nano tanks. These snails are fantastic algae eaters and will not breed in freshwater, so you don’t have to be concerned about any snail population explosion.
Their shell patterns also bring in just an extra little visual interest to the aquascape,.
How to maintain or fine-tune a 20cm Nano Tank Aquascape?
One of the biggest things regarding having a 20cm Nano Aquascape is the maintenance. While this may be true that nano tanks are smaller and thereby are considered to be less labor-intensive compared to larger setups, the truth of the matter is that they tend to be more challenging to maintain. In such a small environment, even minor imbalances could very well spiral out of order right away.
But over the years, I had developed a series of strategies that kept my nano tanks healthy and thriving.
Water Change Importance
If I had to give one word of advice to someone keeping a nano tank, it would be water changes: never neglect them. On a tank of only 20cm, water quality would plunge so much faster than it would in a larger tank. It takes just a small accumulation of nitrates or minor algae bloom to make all the difference in the health of your plants and livestock. For this reason, I recommend doing small and frequent water changes, about 20-30% twice a week, rather than larger water changes less frequently.
One thing I’ve noticed in my own experience is that stability is key.
Nano tanks are pretty sensitive when it comes to water chemistry, so having your parameters in check is a must. I regularly test my water and am especially attentive to ammonia, nitrites, and nitrates, as long as everything’s in check. I also find that with regular water changes my nano tanks seem to stay much more in balance, and I can avoid a lot of the issues that usually plague little tanks, like algae bloom or stressed fish.
I remember a time when I got overconfident and forgot to do my regular changes of water for about two weeks.
I was thinking, “It’s a small tank; it would be fine for a while.” Well, I couldn’t have been any wrong. A number of weeks passed until algae started seriously coating my well-placed Seiryu stones, and plants began to look every so slightly worse for wear. It served me well as a reminder that even a nano in good run could fall out of balance in no time if you weren’t on top of your maintenance routine.
Pruning and Trimming One of the most enjoyable things about nano aquascaping is watching your plants grow and develop over time. Of course, in a 20cm tank, that growth has to be carefully managed. While some plant species barely grow fast enough to ever want it trimmed all that much, such as Anubias nana petite or some Cryptocoryne varieties, other plants can easily overwhelm a small tank in a limited period of time if left unchecked. Even low-maintenance plants like Bucephalandra require the periodic trim to stop them from overshadowing other elements in the tank.
I’ve found regular pruning is quite good, not only visually but keeping the plants healthy as well. It’s very easy in such small spaces where plants can really get in the way of the light and cause algae to take over, or for more slowly growing sorts of things to perish in the lower layers of the aquascape. I make sure to lightly prune all my plants every 2 weeks or so. This helps the aquascape to have an open, airy feel while making certain all of the plants are subject to receive the light and nutrition they require to survive.
A little trick I find useful in pruning is to keep them as close to their natural appearance as possible without letting them crowd each other out. What I have noticed-to allow plants the space to fill out, even in a small tank, provides a look more harmonious than is often seen. Selective pruning, I also find, helps in guiding the viewer’s eye through the aquascape; probably, it makes the tank appear larger than it really is. Algae control is an endless fight.
Algae control in nano tanks is a common theme of discussion among aquarists, and rightly so. In a system that has no more than 20cm, algae can become problematic if the keeping of it goes uncontrolled. Indeed, I have fought my share of battles with algae in my nano tanks, but through time I have learned a few tricks to help me keep it under control without using aggressive means.
But again, the first line of defense is proper lighting. With a nano tank, it’s far too easy to overdo the lighting-especially if you’re trying to grow plants which require high levels of light. I have learned to dial back my lighting to 6-8 hours a day and take advantage of a timer to make sure it runs with consistency.
I’m also strict about LED lights, which should be proportional to the size of the tank itself. Too much light, and you invite an algae explosion; too little, and your plants just cannot stand a chance. It is all about balance. Another key to algae control is a good balance of nutrients. I have found nano tanks tend to show imbalances quite often, especially if you are using fertilizers. What works best for me is dosing the liquid fertilizers in really small doses in my nano tanks. I usually go with an all-in-one fertilizer covering micronutrients and macronutrients, but I dose at half of the recommended strength so as not to overwhelm the little tank with excess nutrients.
But naturally, the biggest player in algae control is the tank inhabitants. As I’ve mentioned earlier, a shrimp or snail here and there can make for excellent algae eaters. I always tend to include a couple of Cherry shrimp or Amano shrimp in my nano tanks, since they do a fabulous job in keeping algae at bay. The same can be said about one of my older setup when I couldn’t get rid of green algae. It was so bad that I just had to try everything. So, by adding literally a few nerite snails, it turned things completely upside down.
And in a number of weeks, the algae were gone, and this tank was nice again. CO2 and Filtration in a 20cm Nano Tank Using CO2 in a nano tank can be a dicey decision. In my experience, the injection of CO2 can make quite a difference in the growth of the plants, but it’s not always absolutely necessary, especially if slow-growing, low-light plants are used. Regarding my 20cm nano tanks, I don’t use CO2 injection unless going for a high-tech setup with demanding plants. If you do plan to use CO2, though, this is one of those instances of which you really want to be very cautious about dosing.
It is very, very easy to overdose CO2 in an aquarium so small, and that’s rather detrimental to both the plants and the inhabitants. I would recommend using a high-quality diffuser and keeping a close eye on your levels with a drop checker. On one of my earlier tanks, I merely over-dosed CO2 and found my shrimp slowing down and gasping at the top. Luckily, I was in time; it was a good reminder that nano tanks can be super sensitive to small changes. For filtration in my nano tanks, I always ensure to keep a small, low-flow filter. In a 20cm tank, the strong water movement can disrupt the aquascape and stress the inhabitants.
It is therefore crucial to choose a filter that will give slow, constant filtration without creating so much turbulence in the water. I have had great success with sponge filters-they do a really good job where biological filtration without creating strong currents is concerned. They are also ideal for shrimp tanks because they don’t provide danger to the baby shrimp. Final Reflections on Nano Tank Aquascaping A few years of experience with tanks ranging in size have developed a certain fondness within me for 20cm nano aquascapes. Small they may be, but the challenges and rewards they pose make creating and maintaining them a truly unique endeavor.
The key to success comes with planning, patience, and attention to detail. All elements in the tank, be they inhabitants or plants with hardscapes, add to the specific ecological balance. Admittedly, a nano aquascape 20cm in length does make for a nice example of how even the tiniest space can be developed into an active, dynamic setting with a bit of creativity and maintenance. Be you an experienced aquascaper or a complete newbie, take it from me-nano tanks are worth trying. No other experience is quite like it, and that feeling you get when you create a miniature underwater world alone will never really feel pretty close to anything else.
