So I’ve been messing around with aquariums for a few years now, right? Started with that basic 10-gallon setup during COVID, moved up to some bigger tanks, thought I had this whole aquascaping thing figured out. Then I decided to try a 50cm tank – which is roughly 20 inches for anyone else who thinks in freedom units like me – and holy crap, it completely kicked my butt. Turns out when you’re working with limited space, every single mistake gets magnified like crazy.
You know how in coding when you’re working on a small, elegant function, every line has to be perfect because there’s no room for bloated solutions? That’s exactly what a 50cm aquascape feels like, except instead of debugging syntax errors, you’re trying to figure out why one tiny rock placement makes your entire layout look like garbage.
I think what initially attracted me to smaller tanks was the same reason I got into aquascaping in the first place – I was living in this cramped apartment near campus, and a huge tank just wasn’t practical. Plus, being a broke college student, a smaller tank meant less money for substrate, fewer plants to buy, cheaper equipment. At least that’s what I thought before I realized how demanding these little tanks actually are.
My first attempt at a 50cm setup was… let’s just say it was a learning experience. I basically treated it like a mini version of my larger tanks, just scaled everything down proportionally. Threw in some rocks I’d collected, planted a bunch of stems, added some carpeting plants, called it good. The result looked like someone had taken a normal aquascape and shrunk it in Photoshop – all the proportions were off, it felt cramped and chaotic, and nothing really worked together.
The problem with small tanks is that there’s nowhere to hide mistakes. In my 40-gallon setup, if I place a piece of driftwood slightly wrong, it might not even be noticeable because there’s so much else going on. But in a 50cm tank, every element is right there in your face. One rock that’s positioned poorly can throw off the entire composition. I spent literally hours moving stones around by millimeters, stepping back, looking at it from different angles, moving them again.
My roommate walked in on me during one of these adjustment sessions and found me crouched in front of the tank with tweezers, obsessing over the placement of a single pebble. He was like “dude, it’s a rock, no one’s going to notice if it’s slightly to the left,” but that’s where he’s wrong. In a small tank, you notice everything. Every imperfection jumps out at you.
The breakthrough came when I started thinking about these tanks more like… okay, this is going to sound weird, but more like user interface design. In CS, we learn about how in limited screen space, every pixel matters. You can’t just cram everything in there – you have to be intentional about what you include, how you arrange it, what you leave out. White space is just as important as content. Same principle applies to small aquascapes.
Creating depth in a 50cm tank is probably the biggest challenge I’ve faced. Without careful planning, these tanks can look flat and boring, like you’re looking at a vertical slice of plants rather than an actual underwater scene. I’ve tried a bunch of different techniques, and some work better than others.
The substrate slope thing really works, by the way. I started doing this thing where I build up the back and corners with extra soil, creating this gradual slope toward the front. It’s such a simple trick but it makes the tank feel way deeper than it actually is. For my current 50cm setup, I’ve got the substrate about three inches deep in the back and maybe half an inch in front. The slope is gentle enough that it looks natural but dramatic enough to create that sense of perspective.
Plant selection becomes super critical in these smaller tanks too. You can’t just pick plants because they look cool – they have to work within the scale of the system. I learned this the hard way when I tried to recreate one of those lush jungle-style tanks I’d seen online. Planted a bunch of different species, mixed fast and slow growers, went for that dense, overgrown look.
Within a month, the tank was a disaster. The faster plants were crowding out everything else, the whole composition was getting lost in this tangle of stems, and the hardscape I’d spent hours perfecting was completely invisible. I had to basically start over, removing probably half the plants and being way more selective about what I kept.
Now I stick to maybe four or five plant species max in a 50cm tank. Usually I’ll do a carpeting plant in front – Monte Carlo works great because it stays relatively small and dense. Some kind of mid-ground plant that won’t get too tall, maybe some Cryptocoryne or small Anubias. Then one or two species for background, and I’m really careful about picking slow-growing stuff. Rotala rotundifolia can work if you’re willing to trim it constantly, but honestly, I’d rather spend my time enjoying the tank than doing maintenance every week.
The equipment situation is interesting with small tanks. You’d think smaller tank equals simpler equipment, but it’s actually the opposite. Small tanks have less stable water parameters because there’s less water volume to buffer changes. So you need really reliable filtration, consistent lighting, proper CO2 if you’re going that route.
I’m running an Eheim Classic 150 on my current 50cm tank, which is probably overkill but better safe than sorry. The thing about external canisters is they don’t take up space inside the tank, which is crucial when you’re already working with limited real estate. Plus you get way more media capacity than those little internal filters.
Lighting was another thing I had to figure out through trial and error. My first attempt used this cheap LED strip that was supposedly designed for planted tanks. The plants survived but they weren’t exactly thriving, and I was getting algae issues because the spectrum was all wrong. Eventually upgraded to a Fluval Plant 3.0, which is honestly more than I wanted to spend but the results speak for themselves.
The CO2 question is tricky with small tanks. On one hand, the smaller water volume means you don’t need as much CO2, so a simple DIY system or even just liquid carbon can work. On the other hand, small tanks have less margin for error, so if your CO2 levels swing around, you’re going to see the effects immediately. I’ve tried both approaches – currently running a small pressurized system with a tiny diffuser, but I’ve had success with liquid carbon too.
Water changes are actually easier with small tanks, which is one of the few advantages. I can do a 50% water change with just a couple gallons, takes maybe ten minutes total. But you have to be more consistent about it because small tanks can’t handle parameter swings the way larger systems can.
The whole experience of setting up and maintaining a 50cm tank has made me a better aquascaper overall, honestly. It forces you to really think about composition, to be intentional about every choice, to focus on the fundamentals instead of just throwing stuff together and hoping it works. It’s like… you know how learning to program with limited memory makes you write more efficient code? Same principle here.
My current 50cm setup is probably the tank I’m most proud of, even though it’s objectively less impressive than some of my larger scapes. It’s a simple Iwagumi-style layout with three pieces of seiryu stone, Monte Carlo carpet, and a few stems of Rotala in the back corner. Nothing fancy, but every element works together, the proportions are right, and it has this sense of depth and space that took me forever to figure out how to create.
The maintenance routine is pretty straightforward now that I’ve got the balance right. Weekly water changes, trim the Rotala when it gets too tall, occasional carpet trimming when the Monte Carlo starts getting thick. Way less work than my jungle tanks that need constant attention.
Looking back, I’m glad I tried the smaller format even though it was frustrating at first. There’s something satisfying about creating a complete underwater scene in such a limited space. It’s like solving a puzzle where every piece has to fit exactly right, and when you finally get it working, it feels like this perfect little world that you built from nothing.
Would I recommend a 50cm tank to other beginners? Maybe not as a first project – I think you need to understand the basics on a larger system where mistakes are more forgivable. But once you’ve got some experience, it’s definitely worth trying. Just be prepared to spend way more time on planning and adjustment than you think you’ll need, because everything matters when you’re working at this scale.
Carlos is a computer-science student who turned pandemic boredom into a thriving aquascaping hobby. Working with tight space and budget, he documents creative low-tech builds and lessons learned the hard way. His tanks are proof that balance beats expensive gear every time.
