Aquascaping 55 Gallons: How To Get The Best Results Out Of The Worst Tank Dimensions For Growing Plants

In the United States, the 55 gallon aquarium is a widely popular set up, but its dimensions make it quite possibly the worst size and shape for growing plants. I think the 55 is such a common tank because it is big enough to be ‘big’ without being too big to be unwieldy. I was able to keep a 55 gallon tank in my 650 square foot one-bedroom city apartment without feeling like it was taking over the place, and growing up I remember being mesmerized every time I went over to my aunt and uncle’s house who had a 55 in their 3,500 square foot two-story with vaulted ceilings and an open floor plan. It’s a perfect size for a doctor’s office waiting room and with a footprint of only 4 square feet, I’ve always been able to find a place for one in my classroom. The size is great, but if you’re trying to grow plants its proportions are kind of a drag. A typical 55 is 48 inches wide, 22 inches tall and 12 inches deep horizontally. If you’re keeping a planted tank, it’s too tall top to bottom and too narrow front to back. You’re going to have a difficult time getting stem plants tall enough to fill out the vertical dimension, get enough light to the bottom for foreground plants without blowing it up with algae, and you’ll be constrained to create any sort of depth front to back. A 40 breeder is much shorter and deeper front to back, but it’s not even 75% the size of a 55. Unless you’re willing to pay a premium for a custom built tank, a 55 is one of the few options in the big-but-not-too-big category.

When I first moved in with my wife after we got married, I was eyeballing a space in our home office to set up my aquarium. Since I had to break down my 55 gallon tank anyway upon moving out of my apartment, like any rational hobbyist, I was kicking around the idea of using the move as an opportunity to upgrade to a bigger tank. There was an existing desk in the space allocated to my aquarium, and the desk had an identical footprint to a 75-gallon tank. Perfect. Of course wedding planning got crazy, wedding plus moving got extra crazy, and by the time we got settled we had already written so many checks with big numbers on them that I didn’t have the stomach to shell out any more cash when I already had a perfectly good aquarium sitting in the basement ready to be set up again. I was a teeny bit bummed that I missed an opportunity, but my new bride gave me her blessing to set up my tank in our home office without requiring an ounce of convincing, so I was thankful. She is a wonderful woman. One evening when we were getting ready for bed, I stopped in the hallway to admire the tank through the open office door. It was quite lovely for that small space. A 75 has the same dimensions as a 55 except it is 18 inches front-to-back instead of 12. Sure a 75 was identical to the footprint of the old desk, but being significantly taller than the desk, it would have likely made the doorway feel rather crowded and overpowered the 10 x 10 room.

When all was said and done, I decided that the 55 was perfect for the space I had, and it’s likely a lot of other people think the same, otherwise they would not be as popular as they are. So how do you get the most out of a setup that is quite possibly terrible for aquascaping? Here is what worked for me.

Go Deep. The 55 is tall, which means it’s going to take a lot to get light down to the plants on the very bottom, overdoing the light is just going to blow it up with algae, and if you’re trying to fill that space with tall stem plants it’s going to take them forever to fill in and you’ll likely be fighting to keep them from looking leggy.

The solution? Use an extra deep substrate. Most planted tanks use a substrate about 2-4 inches deep which leaves about 18-20 inches between the bottom and top of the tank. Use a substrate 6-8 inches deep and you’ve closed that distance to 14-16 inches. It might not seem like much, but remember that light doesn’t penetrate water all that well compared to air...our atmosphere is about 300 miles thick while the photic zone in the ocean is only about 650 feet deep.

Another advantage to the deep substrate is that it serves as a gigantic biofilter. Sure it’s not as sexy as an expensive canister filter that looks like R2D2 with hoses attached, and no you won’t be filling a giant sump with a bunch of those space-age looking plastic bio balls, but it gets the job done. Remember that the whole point of using biological media is simply to provide a surface for good bacteria to grow, as in the ones that convert ammonia to nitrites and then to nitrates. A 55 gallon tank with a 6-inch substrate holds almost 3,500 cubic inches of biological media. Try fitting all that into your canister filter. Additionally, so many of us fret over high nitrates in our tanks. An extra deep substrate allows a hypoxic layer to develop. For most aquariums, the nitrogen cycle ends with nitrates, which we remove through water changes. I don’t know about you, but water changes are by far my least favorite part about maintaining an aquarium. If your substrate is deep enough to develop an oxygen-poor environment, that is where the extra good bacteria live. These guys are able to consume nitrates, which to an aquatist is a wonderful favor. I’m not sure I’d advise to go for a zero water change approach, but smaller, less frequent water changes would be a welcome lifestyle upgrade for all of us.

Now I know what you’re thinking. You’re taking some measurements and doing some math and scouring the internet for the best bargain on ADA Aquasoil or Flourite in your favorite color and wondering if your bank would allow you to take out a loan for the most expensive dirt that money can buy. Before you spend a dollar, please stop and read on! Unless you’re Leo DiCaprio’s character from Wolf of Wallstreet and use $100 bills for…eh…anything other than spending to put it politely, don’t try to fill your 55 gallon tank with 6-8 inches of Aquasoil or Flourite. You really only need as much as you would use normally, so don’t freak out. Your goal should be to raise the bed of your substrate 2-4 inches and then put your good substrate for your plants on top of that.

What worked for me? I used a layer of pool filter sand capped with a piece of mesh screening to prevent the two layers from mixing. Even when I’ve pulled out plants with extensive, deep roots like sword plants, everything stayed where it should have. It effectively raised the bottom of the tank several inches and provided a nice dense sturdy layer to put my main normal aquarium substrate on top of. Gravel might likely be too coarse, but regular “play sand” or sandbox sand from your local hardware store would be a cheaper alternative Just make sure you rinse it thoroughly first or your water could be cloudy for weeks. You will pay more for pool filter sand, but it’s ready to go right out of the bag with minimal rinsing, so you’ll save yourself some headaches there.

Cheat with hardscape. Ok, it’s not really “cheating” per se, but you might want to forgo the idea of trying to get background stem plants to grow all the way to fill the entire vertical depth of the tank. This is especially true if you’re going for a low light low tech setup. Crypts, swords, Anubias and java ferns only grow 6-8 inches at max, but the fun thing about some of those species is that they’re rhizome plants and therefor grow epiphytically, which is just a fancy science word meaning “on anything that’s not the ground”. Some tall pieces of driftwood with a bunch of rhizome plants attached to them is just as good as, if not better than filling the vertical space with a forest of stem plants. I’ve seen sewing thread, monofilament fishing line, and even specialized super glue sold at aquatics shops to anchor rhizome plants to hardscape, but my preferred method is small black cable ties. They are a lot easier to manipulate and sturdier than thread or fishing line, you can cut the cable tie away after a few weeks when the plant has anchored itself to the hardscape, or you can leave the cable tie in place and eventually the plant’s leaves will just grow around it enough that it will be all but invisible. Epiphytes are awesome because they give the viewer the illusion of the scape being wild and natural, and also as they grow their roots will cascade down from the driftwood giving the piece a vibe reminiscent of the planet Pandora in Avatar.

Another option would be to stack flat or rectangular rocks up in a stare step of a terraced layout. Again, enter our friends the epiphytes, Anubias and java fern, and you have some beautiful hardscape that fills the vertical dimension of the tank along with some hardy, low maintenance vegetation. Cable tying plants to large flat rocks might be cumbersome, but other options are wedging their rhizomes between cracks in the rocks, drilling holes in the rocks with a masonry bit in order to thread cable ties through or using super glue. Also you could purchase a few extra rocks to break up into smaller pieces and then cable tie the plants to the small pieces giving you some moveable plants to play with and change the aesthetic of your scape on a whim.

If you really want to grow crypts or swords or among your hardscape or maybe try for some stem plants up closer to the light, you can get mini clay pots in the gardening section of your local hardware store, fill them with plant substrate and place them up within your hardscape. You can leave the pots as they are (I’ve been wanting to do a tank with clay pot hardscape for awhile) or you can situate them within the rocks such that the rocks hide the clay pots. That will allow you to have plants growing in plant-specific substrate but situated well above the main substrate. If you’re using large flat rocks or pavers to create a terracing, then it might be a good idea to line the bottom of the tank with egg crate to more evenly distribute their weight on the glass bottom of the tank.

Lose the middle ground. The past two points had to deal with how to handle the tank’s particularly tall vertical dimension, but the narrow horizontal depth can make things very cramped very quickly if you’re trying to design a scape with some element of horizontal depth. If you click around the plant section on a site like LiveAquaria.com, you’ll find plants sorted by size into foreground, midground and background categories. Your 55 only leaves 4 inches for each of these layers, which makes things REALLY tight. Sometimes it’s best to pick your battles. Forget about the mid ground, and divide your tank into foreground and background when it comes to perspective.

The background is the easy part. Stem plants grow nice and tall to fill in that vertical dimension, and while the 55’s proportions make that a bit challenging, we’ve already talked about how to overcome that by raising the substrate and cheating with hardscape. The foreground is a little trickier. Carpeting plants are an obvious choice for foreground plants because they are lush and grow horizontally via runners to fill in the space where they are grown. The drawback to carpeting plants is that they require a lot of light. Not only will they have to compete with the stem plants for light, but also the light has to penetrate a lot of water given the tank’s tall vertical dimension. Don’t let my advice deter you from using or trying carpeting plants if that’s your thing. I just find that there are easier alternatives and maybe you’re just not as lazy as me!

I’ve been loving some Anubias plants in my foreground because they are slow growing and stay relatively low. Crypts are great, too, and they stay short when grown under low light in an inert substrate. Since I’ve upgraded my lighting, substrate and liquid fertilizer dosing, my crypts are trying to take over my tank, which is not a bad problem to have! I’m currently in the process of aggressive trimming in order to keep them low, bushy and compact. I’ve even had some luck growing stem plants in the foreground, but they grow fast and get leggy fast, so keeping them bushy and compact is a matter of cutting them down and re-planting them frequently, so that’s a lot of gardening. Also, you don’t have to use just plants in your foreground, either. The foreground is a great place for hardscape like low pieces of driftwood and softball-sized rocks. Situating rhizome plants into cracks in driftwood and having plants poking out between medium-ish sized rocks gives the viewer the illusion of the scape being natural and not too carefully arranged.

Conclusion. Ultimately, what started as a missed opportunity to upgrade to a bigger, better tank turned into an opportunity to play with space and perspective in unique ways, and I think I like it better. Additionally, my very cheap, very small, very colorful and very happy livebearers have been blowing up, and the tank is full of maybe one hundred or more little fish all one inch or smaller. Maybe the zen master aquascaping set would call it too busy of a presentation, but it’s a busy scape full of a bunch of busy fish, and it’s endlessly entertaining. I spend a half hour or more every morning eating breakfast, drinking coffee and watching my fish, and without fail, every morning I have to pull myself away from the tank or risk being late for work. I’m sure it will evolve as is the tendency for all aquariums, but for now it’s perfect by my mark. I hope you all enjoy your tanks as much as I enjoy mine.