Tiny tanks are a special kind of madness. I say this with love, having set up dozens of pico aquascapes over the years and currently maintaining three on my desk alone. There’s something addictive about creating complete underwater worlds in vessels smaller than a coffee pot.
It’s like the difference between painting a mural and painting a miniature—both are art, but one requires tweezers and possibly a magnifying glass. Let me tell you about my first attempt at a pico tank—it was a spectacular failure that taught me more than any success could have. I had this gorgeous handblown glass vase, about two liters in volume, with gently curving sides that caught the light beautifully.
I spent weeks planning a minimal hardscape with just a small piece of spider wood and some tiny anubias petite. In my mind, it would be this perfect jewel of an aquascape—a miniature work of art. What I created instead was a masterclass in how quickly a small volume of water can go bad.
Within three days, the water was cloudy. By day five, I had an algae bloom that turned everything a lovely shade of pea soup. The shrimp I had so carefully selected were desperately clinging to the filter intake, trying to get more oxygen.
It was a disaster, and I had no one to blame but myself and my complete failure to understand the fundamental challenges of tiny tanks. So what did I learn from this embarrassing episode? The smaller the water volume, the faster things go wrong AND the harder they are to fix.
In a pico tank, there’s almost no room for error. But that’s also what makes them so rewarding when you get it right. After years of trial and error (and honestly, mostly error at first), I’ve developed a few basic principles for setting up pico aquascapes that actually survive beyond the initial “wow, that looks pretty” phase.
First up: containers matter more than you think. Not all small vessels are created equal. You want something with a relatively wide opening for maintenance access (trust me, trying to aquascape through a bottle neck will drive you to drink), stable sides that won’t tip over easily, and preferably a shape that maximizes surface area.
Surface area is critical for gas exchange in tiny tanks—the more water surface exposed to air, the better your oxygen levels will be. I once tried to set up a pico tank in an antique apothecary bottle because it looked cool. The narrow neck made planting nearly impossible, water changes were a nightmare, and the tall, narrow shape meant terrible surface area to volume ratio.
It crashed within two weeks. Learn from my mistakes—function first, then form. For substrates in pico tanks, you need to think small in every sense.
Fine-grained substrates work better than large pebbles simply because of scale—a single large piece of gravel in a pico tank is like having a boulder in a standard aquarium. I prefer using aquasoil specifically designed for aquascaping, since it’s nutrient-rich and helps with plant growth in systems where adding fertilizers can be tricky. But depth matters—don’t go overboard.
In most pico tanks, 3/4 to 1 inch of substrate is plenty. Any more than that and you’re just taking up valuable water volume. The hardscape is where many pico tanks go wrong.
The temptation is to cram in one awesome centerpiece—a cool rock or piece of wood that dominates the tank. Fight this urge! Scale is everything in pico aquascaping.
I have literally spent hours walking through nature looking for the perfect tiny pieces of driftwood or pebbles that have interesting shapes at a miniature scale. Aquascaping supply stores rarely carry pieces small enough, so I’ve become that weird guy who collects pebbles from stream beds and keeps them in labeled containers. My current favorite pico tank uses a piece of driftwood no bigger than my thumb, but it’s perfectly branched to create the illusion of a fallen tree in a forest.
It took me three months to find that piece, and yes, my friends did stage an intervention about my “unhealthy obsession with tiny sticks.” They just don’t understand the hobby. For plants, think beyond the usual aquarium selections. Many common aquarium plants are way too large for pico systems, or they grow too quickly and will overwhelm your tiny tank in weeks.
Moss is your friend here—different varieties of java moss, Christmas moss, and flame moss can be used to create the appearance of different plant types at a miniature scale. Anubias nana ‘petite’ is perfect, as are the smallest varieties of bucephalandra. Look for tissue-cultured carpet plants too—baby tears (HC) and monte carlo can create the impression of meadows and lawns when trimmed regularly.
I’ve had good success with Hydrocotyle tripartita ‘Japan’ in pico tanks—it’s small-leaved but grows relatively slowly if you keep light levels moderate. Just be prepared to trim it weekly, or it will take over. That’s the thing about pico tanks—maintenance isn’t necessarily less frequent than larger tanks; it’s just performed with smaller scissors.
Filtration is tricky in pico systems. Many commercial nano filters are still too powerful and create too much current for tanks under 3 gallons. I’ve experimented with a lot of options, and for true picos (under 2 gallons), I’ve had the best results with simple sponge filters powered by the smallest air pumps I can find.
I then modify them by cutting down the sponge to an appropriate size and using an air flow regulator to reduce the bubbling to the absolute minimum needed. For something with a bit more control, small internal filters designed for betta tanks can work if you baffle the output. I’ve used everything from filter floss to 3D-printed custom baffles to reduce flow to an appropriate level.
The goal is movement without visible current—just enough to circulate water without sending your tiny plants and hardscape elements flying across the tank. Lighting is another challenge. Most commercial aquarium lights are too powerful for pico tanks and will quickly lead to algae problems.
I’ve found that small LED desk lamps can work perfectly if positioned correctly. Look for ones with adjustable brightness and color temperature around 6500K for the most natural plant growth. The key is to start with much less light than you think you need and gradually increase if plants aren’t thriving.
It’s far easier to add more light than to fight back an algae bloom in a tiny tank. I learned this lesson the hard way with a 1.5-gallon vase setup where I used a light that was too strong. Within days, the glass walls were green with algae, and the carefully arranged moss was suffocating.
Now I start with minimum lighting and slowly increase over weeks while watching plant and algae growth carefully. Now for the controversial part—livestock. Let me be absolutely clear: most pico tanks should not contain fish.
The volumes are simply too small to be stable enough for vertebrates. Even bettas, which are often sold with tiny tanks, deserve at least 5 gallons with filtration and heating. But that doesn’t mean pico tanks must be lifeless.
Small shrimp colonies can thrive in well-established pico systems. Neocaridina varieties (cherry shrimp and their color variants) are hardy and perfect for tiny tanks, as are certain micro snail species. My favorite pico tank contains exactly three cherry shrimp and two mini ramshorn snails.
That’s it. And they’ve been thriving for over a year, breeding occasionally (though population remains controlled by limited resources, which is exactly what you want in a system this small). Water changes are the lifeblood of pico tanks.
There’s no way around it—you’ll be changing water frequently. In the first month after setup, I typically change 50% of the water every other day. Once the tank stabilizes, you can sometimes reduce to twice weekly, but I never go less than that.
The good news is that changing water in a one-gallon tank takes about two minutes, so it’s not a huge time commitment. The method matters though. I use a dedicated turkey baster for water removal (which earned me some very strange looks the time I accidentally grabbed it for actual cooking).
For refilling, I use airline tubing attached to a small funnel to direct water flow against the glass to minimize disturbance. Always use pre-treated water at the exact same temperature as the tank—in small volumes, even minor temperature shifts can stress livestock. Temperature stability is another challenge with pico tanks.
The smaller the water volume, the more quickly it responds to ambient temperature changes. I keep my pico tanks away from windows, heating vents, and air conditioners. If your home experiences significant temperature fluctuations, pico tanks may require more intervention.
Some aquascapers use small heating mats designed for reptile terrariums, placed beneath or behind the tank (never inside, as most aquarium heaters are too powerful for pico volumes). The last thing I’ll mention is patience—possibly the hardest part of pico aquascaping. These tiny systems take just as long to mature and stabilize as larger tanks, sometimes longer.
My most successful pico setups ran for 4-6 weeks with just plants and hardscape before adding any livestock. This cycling period is critical for establishing the beneficial bacteria that will keep your tiny ecosystem functioning. During those waiting weeks, I watched parameters like a scientist, testing ammonia, nitrite, and nitrate levels daily.
I added beneficial bacteria products designed for aquarium cycling, being careful to dose appropriately for the tiny volume. Only when I recorded zero ammonia and nitrite for two consecutive weeks did I consider adding shrimp. The reward for all this meticulous attention to detail?
A complete, self-sustaining underwater world that fits on a bookshelf. There’s something magical about creating a balanced ecosystem in miniature—it’s like having a tiny window into another world right on your desk. When done right, a pico tank can be more visually impressive than tanks ten times its size, simply because of the scale challenge it represents.
Just be prepared for the questions. My most successful pico tank sits on my desk at work, and I’ve lost count of how many meetings have been derailed by someone pointing at it and asking, “Is that an actual aquarium? How does that even work?” Which, of course, is my cue to spend the next fifteen minutes talking about the nitrogen cycle and the importance of surface area for bacterial colonization while my colleagues slowly back away.
Their loss—they’re missing out on the special joy that comes from creating entire worlds in very small glasses of water.
