This really is a sweet spot in terms of size for aquascaping in a 20-gallon tank, as it is not too small to stifle creativity and yet not so large that it can become totally overwhelming in every respect, both in terms of time and maintenance. I have found 20-gallon aquariums to be that satisfactory middle ground whereby an aquascape truly becomes captivating, offering room for intricate design, space where your fish and plants can prosper. Over time, I have tried all sizes of tanks, but 20 gallons keeps coming back, for many reasons: from its footprint being manageable to the balance it allows in plant and livestock selection.
Today, I’d like to share with you some of my personal experiences, preferences, and things learned along the way.
Why I Love Working with 20-Gallon Tanks when Aquascaping
When I started aquascaping, I started with a small tank, just like everybody else with those typical 5- and 10-gallon set-ups. These can be fun, though I soon found out that the problem with smaller tanks is the great limitations to plant growth, as well as fish stocking, not to mention the aquascaping materials. The smaller the space, the more difficult it is to come up with a design that is not only natural-looking but also healthy for the plants and animals living there. Meanwhile, the 20-gallon tank provides an excellent compromise. It is small enough to sit comfortably on a modest stand or counter space, but large enough to create depth and dimension with hardscaping material like rocks and driftwood, and you can add other plants without crowding them.
I still remember one of my first successful 20-gallon aquascapes being an Iwagumi setup using three Seiryu stones and a carpet of Hemianthus callitrichoides, commonly referred to as dwarf baby tears, and even with such a minimalistic approach, the scale of the tank allowed me to develop the type of visual depth that is highly unrealistic in small tanks.
A 20-gallon aquarium is a great and more forgiving tank for aquascapers, mainly starting with their aquascaping journey, or perhaps from smaller tanks, where you may try different aquascaping styles such as Dutch, Iwagumi, or Nature style layouts. Believe me, this size of the tank gives you the opportunity to unleash your creativity without driving yourself crazy.
Choosing the right style for a 20-gallon tank In a 20-gallon tank, I like to use either Nature-style or Iwagumi setups. These provide for me the right amount of complexity versus simplicity. In a Nature-style aquascape, you can implement a lot of diversity-from driftwood, even to rocks, mixed plant species to resemble an underwater forest.
This I find particularly rewarding, as it emulates natural biotopes that may occur in nature-something I try to emulate as closely as possible in my aquascapes.
On the other hand, Iwagumi, especially in its simplicity and the thoughtfulness behind the placing of the stones, carries an almost Zen-like appeal. It’s all about finding harmony with the elements. I once spent hours-seriously, hours-on one of my earlier 20-gallon Iwagumi tanks just in rearranging the positioning of three rocks. I was trying to achieve that perfect asymmetrical balance which would draw the eye from one side of the tank to the other naturally, creating an illusion of a huge landscape in a small space. Well, it was a test of your patience, but when you get it right, the effect is stunning.
Anecdote of a Favorite of Mine
I can remember one case: I simply went all-out on a Nature-style scape in a 20-gallon-long tank, using driftwood to create the image of a tree branch arching over the substrate, and complementing it with a variety of ferns, mosses, and Anubias epiphytes.
This, in fact, makes me proud, as for the first time my moss carpet had thrived; at other tanks I’d always had problems with keeping healthy moss, as uncontrolled fluctuation of water parameters was beyond my control. Here, in this tank, I found some sort of balance that allowed the moss to thrive, and the result was a nice green landscape, almost like a mini forest floor. It has been the point of pride in my home for a long period.
Ways to Create a Stunning 20-Gallon Aquascape
Planning a 20-gallon aquascape always requires proper preparation for success. Basically, I prepare for three main parts before adding the first drop of water into the tank: substrate, hardscape, and selection of plants. From all years of building and observing these aquascapes, I understood that what is chosen in these three areas will determine and decide aesthetic qualities of the tank but also its long-term health.
Choices of Substrate and Layout
This is one of the most important aspects that many starters like to bypass, but essentially it is the most basic part of any aquascape. At the very beginning, I thought plain old aquarium gravel would do the job. Well, plant growth was poor-it’s really a headache to maintain water parameters. Nowadays, I swear by using nutrient-rich soil substrates like ADA Aquasoil to supply a decent dose of both nutrients for the plants and something which would help to support root development.
One thing I did with most of my smaller tanks, like 20 gallons, was slope the substrate so that the back of the tank turned out to be a little higher than the front. That gave it much more depth in aquascape compared to what one might have achieved with the naked eye, apart from being visually larger than actual size. The back, I would build up, portions of Aqua Soil mixed with the fragments of Seiryu Stone to have something more substantial in structure and regularity for stability. This helps not only to add dimension but also can hold the slope in its place over time.
Hardscape: Rock and Driftwood Installation
Hardscapes in the form of rocks and driftwood are pretty much the skeleton of your aquascape. In a 20-gallon tank, the balance between too much and too little when it comes to hardscaping can get tricky.
I have learned the hard way that over-crowding it with large pieces of driftwood or too many rocks can make the scape look cramped and unnatural. In place, I try to adapt the rule of composition known as the “golden ratio,” where around two-thirds of an open space should fill in the main bulk of the tank and the hard-scape be left just about occupying around one-third. One example of a layout that I have done includes large pieces of spider wood, angled to create the visual effect of tree roots extending down towards the bottom of a riverbed in a 20-gallon tank.
This is one of my favorite hardscapes, as the intricate lines in the wood tend to draw the viewer’s attention. To complement the spider wood, I used dragon stone for accents to provide contrasting texture and color.
The challenge with any 20-gallon tank is finding a balance between creating an appealing visual structure without taking up space some plants and fish will need to thrive.
Plant selection involves the mixing of plant species together for maximum impact. By far, plant selection is one of my favorite aspects of any aquascape project. You can certainly try to be a little more experimental with plant species in a 20-gallon tank, whereas smaller tanks allow for fewer options. Over time, I’ve developed a fondness for using a combination of carpeting plants like dwarf baby tears or Monte Carlo, mid-ground plants like Cryptocoryne or Java fern, and tall background plants such as Vallisneria or Rotala. One of my staple combinations in a 20-gallon tank is carpet plants up front, with larger, bushier species towards the back.
A good example is a dense carpet of Monte Carlo up in the front transitioning into the back with a jungle of Rotala H’ra and Hygrophila pinnatifida.
Such plants put together can create a multi-layering effect, adding depth and color variation in the tank. In fact, it’s very rewarding to observe such plants grow over time and fill up a space. Another plant I just love using in 20-gallon setups is Bucephalandra. It is very slow-growing, doesn’t need much maintenance, and can do perfectly well in low-tech settings. I attach it to pieces of driftwood or rocks, and over time it becomes one with the scape, almost like it was always meant to be there.
Lighting: The Proper Balance of Light Another area where I find most aquascapers have gone wrong-my younger self included-is on the lighting. A 20-gallon tank will easily grow algae with too much light and be stunted with too little. Invest in a high-quality, variable LED light, I say. Nowadays, I would depend on models like the Twinstar 600E, which allows fine-tuning of both intensity and spectrum.
A 20-gallon tank, on the other hand, gets a moderate amount of lighting from me: enough to keep the plants healthy without fostering too much algae growth.
One challenging aquascape initially had my lighting too high, in which, after a few weeks, the algae actually exploded. Adjusting the light intensity, and incorporating a shorter photoperiod-from 8 hours down to 6 hours per day-the algae did subside, indeed, and the plants rebounded, healthier than ever. At times, it is experiences like this that truly show me that less is more when it comes to lighting.
The Battle of the Algae Bloom
Speaking of algae, one really unforgettable experience was the fight against green algae in a 20-gallon Nature-style tank. I had really nice aquascaping going-on: intricate hardscaping of dragon stone and a well-thought-out layout of plants. It seemed as though everything was fine for a couple of weeks or so until the green algae bloom hit. Gutted. My pristine scape soon became a green nightmare. I’d tried everything from adjusting the light to cutting back on feeding, and yet nothing would make the algae leave.
Finally, I decided to introduce a few Amano shrimp into the tank, together with some nerite snails, in the hope that they would become my algae-cleaning crew.
To my surprise and relief, they had devoured most of the algae within a few short weeks. My plants were thriving again, and the balance between lighting, plant growth, and algae was resumed. I learned from that experience just how delicate the ecosystem can be in an aquascape.
Aquascaping Your 20-Gallon Tank-Versatile Maintenance to Ensure Success
Now that your 20-gallon aquascape is running, it’s time to do the real work: maintenance. In my experience, the art of a good aquascape isn’t just how you set it up in the beginning but also how you care for it. There’s nothing worse than watching your aquascape lose that beauty over time because no one has taken the time to care for it.
Trust me, I have been there, and after some years of trying and testing, I learned that constant and mindful maintenance is the secret to making your aquascape as fresh and healthy as when you planted it.
Water Changes and Parameters: Stability is the Key
A 20-gallon tank, of course, needs water changes to maintain the health of your plants and fish. I am doing a 25-30% change in water once a week. This may be often to some, but this is very, very important in preventing nitrate buildups and other products of waste that may stunt your plants and hurt your fish.
One thing I did learn from this whole experience is that having stability in your water parameters is, in fact, a lot more important than hitting on any given number.
For example, with one of my earlier 20-gallon aquariums, I simply couldn’t resist playing with the pH and hardness, seeking to reach some kind of “optimal” values I could find on web forums. In fact, it was all those changes that started stressing my fish and plants. Nowadays, stability means more to me. If my pH is slightly higher or a little lower than what is recommended, yet everything is doing great in the tank, I just leave it well enough alone.
In terms of water parameters, I tend to go for the following in my 20-gallon tanks:
Temperature: 72-78°F, depending upon the variety of fish and plants I am keeping.
pH: Between 6.5 and 7.5, though there is usually some leeway outside this range as long as it’s stable. Ammonia/Nitrites: Always 0 ppm, of course.
Nitrates I’d like these to remain under 20 ppm, assisted by regular water changes and a dense planting scheme.
Trimming and Pruning Plants: An Essential Step
Early on, I learned that pruning is absolutely crucial in order to maintain a refined aquascape throughout the process. Plants such as stem plants-Rotala, Ludwigia, and others-can grow extremely fast and should be cropped fairly regularly so that they do not quickly dominate the tank. I like to trim these plants once every two weeks to maintain the shape of the aquascape. Plants that grow slower, like Cryptocoryne or Anubias, get trimmed by me only when necessary, which usually is every couple of months.
One of the things that I like most about aquascaping is how plants tend to change over time. First, there’s the 20-gallon tank I remember, in which I had a small bunch of Rotala in the background. Over some months, the little bunch was now thick and colorful in hue. With regular trimming, it allowed me to shape it into a cascading waterfall of green and red leaves, adding depth and dimension to the aquascape.
Dealing with Common Problems: My Battle with Black Beard Algae
It doesn’t matter if the aquascaper is of the most advanced class-outbreaks always happen, yet for some reason, this black beard algae is proving to be one of the most resilient in my 20-gallon tank. I can recall quite well one such tank when, overnight, it seemed like BBA sprang into being. First, it started as small tufts on the edges of my rocks and driftwood, yet predictably enough, soon made its way onto my plants.
With some research and discussion with other, more experienced aquascapers, I suspected that the problem was fluctuating CO2 levels and inept water circulation. By increasing the CO2 injection and installing a small circulation pump, it was possible to improve the flow around the tank. In combination with some manual removals and a few dosages of liquid carbon-which can help kill BBA-it had been possible to bring the outbreak under control within a few weeks.
CO2 Injection: To Inject or Not to Inject?
Now, speaking of CO2, this happens to be one of the most highly debated topics within aquascaping, and, of course, even more so when working on the scale of a 20-gallon tank. I am a huge supporter of adding CO2 into an aquascape if you want the plants inside it to grow fast and be as vibrant as possible. For me, from experience, adding CO2 does not just speed up the growth of plants but actually makes them healthier and more colorful. In my current 20-gallon high-tech setup, I employ the use of a CO2 system on the light cycle to keep levels optimal for photosynthesis of the plants.
That being said, my objective level of CO2 is always at around 30 ppm, which, of course, I can monitor by using a drop checker. This way, it has been possible for me to keep various types of demanding plants such as Glossostigma and Dwarf Hairgrass. That said, CO2 is absolutely not necessary to achieve a successful 20-gallon aquascape. I have indeed had great success with low-tech systems, using limited light and hardy plants such as Java fern, Anubias, and Cryptocoryne. For the new hobbyist or for those that want, quite rightly, less high-maintenance tanks, skipping CO2 is still possible and perfectly fine, providing the proper plant mix is chosen and a routine maintenance schedule followed accordingly.
Personal Story: The Day My CO2 System Failed Over the years, I have had my fair deal of mishaps with the CO2 system. Once, I remember the malfunctioning of my CO2 regulator respiration, which raised the level of CO2 in my 20-gallon tank overnight. I woke up to find all my fish at the surface, gasping for air-nothing too unusual than a heart-stopping moment. I immediately turned off the CO2 and then added an air stone to oxygenate the water. In doing that, I unfortunately lost a few fish. That experience had taught me a valuable lesson-when it came to my CO2 system, I needed a backup plan just in case anything went wrong with it.
It taught me to monitor my tank closer, with a replacement air stone ready to be popped in at a moment’s notice. Fish and Invertebrate Selection for a 20-Gallon Aquascape The correct choice of fishes and invertebrates usually is the key to maintaining correct balance in a 20-gallon tank. I prefer small, peaceful fish that complement the aquascape rather than overshadowing it. Some species I would recommend for a 20-gallon setup are: Neon tetras or Ember tetras: With their schooling behavior, neon tetras are perfect in smaller tanks, with their colors being beautifully contrasted by the plants. Ottocinclus catfish: Small algae eaters that are really good for cleaning your plants without causing any damage to them.
Amano shrimp: these, as mentioned before, are the best algae-eaters. I put them in just about all my aquascapes. Fascinating to watch them go about their chores. One of my favourite 20-gallon tanks had a school of 12 Ember tetras in it, with a few Amano shrimp and a pair of Nerite snails. The body color of the Ember tetra brought out an incredible orange, contrasting so imaginatively against the rich green foliage of the plants. Shrimp and snails quietly worked in the background in controlling algae growth. All these combined to create one little ecosystem that was as functional as it was catching to look at.
Conclusion: The Joy of a 20-Gallon Aquascape Ultimately, aquascaping a 20-gallon tank is about balance: plants to fish, hardscape to open space, maintenance to enjoyment. Over the years, I have come to realize that my most successful tanks are the ones where I took the time to plan properly, maintained a regular routine, and mostly enjoyed the process. Whether you’re just beginning or have been aquascaping for years, this 20-gallon tank will offer you endless possibilities of creativity and beauty. So, if you are thinking of your next project, do not underestimate what a 20-gallon tank could do. Use the right approach and make it into a wonderfully amazing underwater world-things you could enjoy for that long time.
