In late August 2025 I decided I needed a break from The Horrors and decided to dip a toe back into the fishkeeping hobby. I was maintaining a 55 gallon goldfish tank, but I really wanted to start dabbling in community tanks and keeping a larger variety of creatures. What I DID NOT want was another big tank to maintain.
While researching small tanks (nano tanks) I came across the Walstad method, which is a low-cost, low-tech, low maintenance dirted ecosystem tank method that relies heavily on plants for cycling . These tanks do not have filters or heaters (and may not even have lighting, if you're able to place it somewhere it can get enough indirect sunlight). I quickly became fascinated with the shrimp bowls and whatnot people were keeping using this method.
I really liked the idea of being able to cheaply set up small one to five gallon tanks that could easily be moved or taken down and didn't require dedicated stands.
Here are some notes on a mostly-native coldwater walstad tank, which is a work in progress.
First Attempt at 5.5 Gallon Walstad
After a ton of research I decided to try a 5.5 gallon Walstad, both for cost and weight reasons. A 10 gallon weighs over 100 pounds, but a 5.5 gallon is a bit more manageable and can be kept on a sturdy piece of solid wood furniture. I got the tank on sale for $12 at PetSmart, and evidently they regularly have 50% off sales for their open tanks.
I harvested some plants from the local lake. This is a typical haul. Aquarium plants can be pretty expensive, so being able to harvest natives made this a lot easier for me.
I used 2 inches of potting soil I happened to have lying around. I didn't want to buy a huge bag of sand, so I got a 5lb back of Mosser Lee black sand for $9 at a hardware store. This 👏 Was 👏 A 👏 Mistake. It took FOREVER to rinse, and 5 lbs was barely enough sand to cap the soil in a 5.5 gallon, and since it was black I had a hard time telling if coverage was good.
NARRATOR: It was not.
When I added water, I ended up with this mess... the soil leeched into the water column, and it did NOT clear up by the next day. I also had gross floaty bits from the potting soil. Even if it settled, adding plants later, or having digging invertebrates, would lead to the soil continuing to leech.
Time to start over. I dumped all that stuff in one of my garden beds and started again.
Second Attempt at 5.5 Gallon Walstad
This time, I bought a 50lb bag of Diamond Black Blasting Sand (DBBS) for about $13. This stuff is dirt cheap (cheaper, actually), it looks great, and it's used by many fishkeepers. It has to be pre-rinsed, which is less prohibitive if you have access to an outside hose. All I did was dump a bunch into a 5 gallon bucket, stick the hose into it to the bottom, and let water run until it was clear. I was honestly surprised by how quickly I was able to rinse this way. This stuff is GREAT. Way better than pool sand IMO.
I also bought a huge ass bag of organic garden soil (Miracle Gro, $13). Goodbye weird Styrofoam balls. I don't have a sifter or care to make one, but I did take a few minutes to pick out the larger pieces of mulch.
I put down 1.5" of soil and capped with 1" of sand. 3" of substrate is when you start to see anaerobic bacteria pockets (I witnessed this with my 55 gallon, which had 3" or more of sand in the beginning).
To add water, I put down a piece of aluminum foil and gently poured conditioned tap water over it until I had several inches of water. From there, I used the longest tweezers I have (I have a bunch, being an electronics hobbyist) to place plants. I used emersed plants (which grow out of the water) as well as fully aquatic plants.
I've had a cool piece of driftwood for YEARS I was never able to properly submerge, and not for lack of trying. I've soaked it for months, boiled it in hot water, you name it. I decided to try anchoring it with fish weights, which were all I had. This... did not work. So no drift for this tank. Which is fine, it honestly took up more space than I realized.
I also threw in some lava rocks to create hiding places. I got a big ole bag of these for $7.
When all was said and done, I spent about $35 on enough substrate to last me a looooong time (probably 5 of these tanks, easily), versus paying $40 for Just Enough Fluval Stratum and aquarium sand for this one tank. So you gotta decide what you want to do but I wanted to stick with the spirit of the thing, which is low cost.
Let's Talk About Plants
I'm starting to appreciate people tend to really underestimate how important plants are. You can cycle a tank entirely with plants and a decent light source. No fish sacrifices, no added ammonia, not even a snail. If you are setting up a heavily planted tank, you'll never see the ammonia/nitrite/nitrate spikes that people commonly use to confirm the tank is cycled.
The plants most efficient at pulling chemical compounds out of the water are going to be floaters and emersed plants, and this is because they have the easiest access to oxygen. Additionally, plants will out-compete algae for nutrients.
Walstad recommends a "siesta" lighting schedule, which is several hours of light, a period of rest, and a second period of light. This allows plants to recover from all the photosynthesis they've been doing.
I ended up experimenting with an inexpensive full spectrum aquarium LED I got online (I think it was $15) and a lamp with a grow light, but I think a 60 watt bulb would also work, and from what I've read cool light is generally most effective. I observed regular pearling, which occurs when submerged plants release oxygen faster than it can be absorbed into the water column, when I had the lights on for a full 12 hours. When I switched to a siesta schedule of about 5 on, 2 off, 5 on, pearling was less frequent.
I ended up sourcing local arrowhead, Eurasian watermilfoil, pond weed, coontail, creeping jenny, and water lettuce (and hydrilla, which I hate so I only use it for goldfish food). I also bought some Amazon frogbit from a LFS. At this stage, I've gone for a jungle approach, letting everything grow to see how it fares. It's been very fun to watch the creeping jenny and others grow runners. The watermilfoil browns over time and the bottom always browns when rooted. I'm reluctant to remove anything from the tank at this stage because I want to see who eats what, but the watermilfoil will shed when it dies back so I may end up trimming and removing that part.
I'm experimenting with overwintering hydrilla in a tall clear plastic container that gets indirect light, and I've also set up a 1 gallon (anchor hocking has these glass 1 gallon containers that look better to me than a standard fish bowl) with watermilfoil and coontail to see if I can get it to continue growing on the side.
Film on the water
Pretty early on I observed a shimmering film on the surface of the tank. Initially, I thought this was residue from the DBBS (which is not a big deal, and you can pick it up by placing a paper towel on the surface), but evidently it is nutrient buildup (biofilm) and invertebrates will consume it so no worries.
SNAILS
Early on, I did a bunch of research on snails because I used to keep Apple Snails (actual canas!) and I wanted to get back into snailkeeping. I did not, however, want to get a bunch of snails with a big bioload that require large tanks. I figure I can support one, maybe two, big snails in my 55 gallon, but for the Walstad tank the bioload needs to be small. I was drawn to ramshorn snails because of their low bioload, the different colors, and the speed of breeding.
About a week after I set up the tank, I was able to add 10 pink baby ramshorn snails. I was slightly paranoid about the tank being fully cycled, but you can add snails to fairly new tank or even use snails to cycle a tank and they roll with it. The package got stuck USPS hell for a few days when was D: but they all survived and as soon as I added them to the tank, set to work exploring and eating.
SO SMALL. Finger included for reference.
Within 2 weeks, I spotted actual babies, which really surprised me because I figured I wouldn't see any for a few months. And I didn't see any eggs, but the tank is really heavily planted. I had to get my magnifiers out to identify them. Less than 1mm. Then I realized oh... these are bladder snail babies! Unsurprising I'd have some hitchhikers, as I recently added the coontail. I have a separate 1 gallon for growing watermilfoil and coontail that I'm also keeping bladders in, so I tossed em in there for now.
I was paranoid about the snails getting enough calcium. You can put calcium in the water column, but as with any nutrient or medication, it is best if it is consumed. Some people add cuttlebone to the tank. I wanted food, and looked up snello and other things but ultimately decided to try out Kats Aquatics calcium-protein chips. The snails freaking LOVE it. They also love algae wafers. I tried giving them a thawed frozen greenbean on a skewer, but I think the skin was too tough for them. So I'll blanched vegetables when I have some on hand.
Parameters
The parameters on this tank have been consistently high ph and very alkaline, with ammonia/nitrite/nitrate being 0/0/0. The hard water is good for invertebrates.
I did notice significant ph fluctuation through the day depending on where the plants are in their cycle.
What's next?
I finally got a GH/KH test kit. The LFS had single kits for $30 each (??? I'm still scratching my head over that one) but I got an API combined kit for like $11. I measured KH 2 (35.8), GH 9 (161.1), confirming I have very hard water.
I would like to add shrimp next. Originally I was considering glass shrimp, which are native, but there are some real challenges there and I decided to go with neocaridina (aka cherry shrimp) which are going to be more forgiving. Shrimp do not like unstable parameters, but the ph fluctuations in my tank are caused by the high plant ratio. Still need to do research I think.
