New Terrarium DIY : Smart + Planted Fish Tanks

I recently stole my husband’s 15-gallon fish tank for my own, wanting to create an underwater garden as beautiful as the coral reef he’d cultivated in the very aquarium I’ve since usurped. Having outgrown the petite tank, in which my husband may or may not have intentionally cram-packed rocks, coral and fish, the tank was up for grabs. I now needed the small tank to experiment with a new spin on terrarium design with an underwater garden. Whereas my current residence isn’t generous with the direct sunlight required for terrariums, here I had the opportunity to design the terrarium, complete with submersible plants, decorative objects and its own set of automated lights.

Admittedly I contribute more to the design of this tank than its maintenance, so this article details the process of designing and automating a relatively low maintenance freshwater aquarium. In other words, the following is a beginner’s guide to smart, planted tanks. Bonus: inspiration aquascaping photos (see full gallery here). 


Terrarium DIY : Initial Setup


An aquarium

If the underwater terrarium is the effect you’re going for, take advantage of smaller tanks to be placed atop accent tables. Smaller sizes, between five and 20 gallons, scale nicely for any setting.

A stand

Many fish tanks come with a stand. For the aesthetically inclined, here are some brands to consider: Fluval and Innovative Marine. For smaller tanks, any raised surface, like a desk, will do.

Example of an artfully designed aquascape

Shown above * Example of an artfully designed aquascape


Aquarium sand comes in a variety of colors and can add to the design elements of your underwater terrarium. Black sand offers a stark backdrop that can be leveraged for high contrast with other items in the tank, while white and pink are other common color options. Different colored sand can be mixed for an even more unique effect, and designer gravel can mix in a blur of neon fun to your sand setting.

Air Pump

The air pump is crucial for freshwater tanks, as it oxygenates the water. Just like humans, fish need oxygen to breath. Though an oxygen exchange takes place at the water’s surface, an air pump will supplement this natural transaction to ensure a happy environment for fish and plants alike.

Air Stone

The air stone is what makes bubbles via the air pump for better oxygen exchange with the water.

Heater with Digital Thermostat

All the living creatures in your underwater terrarium will thrive at the right temperature, so a heater is a most important. Heaters with a digital thermostat will offer easy, visual cues as to the condition of your tank. Blue means the water is too cold, red is an obvious warning that things have overheated. See green on the digital reader, and you’re in the clear.

Water Filter

This provides a mechanical filtration of the aquarium’s water to remove fish waste and excessive food particles. I recommend an HOB filter, which attaches on the rear of the tank.


Central to the design of your terrarium are lights. LED lights are most effective for aquariums, consuming the least amount of power with minimal design restrictions. This means LED lights are also the best-looking for your tank. Aquarium lights can run the full spectrum of colors, creating endless effects for all the components of your underwater terrarium.

Cooling Fan

For closed canopy tanks (those with tops), a cooling fan can keep the aquarium from overheating.

Glass Cleaner

Be sure to see your beautifully designed waterscape by keeping the glass clean.

Aquascaping thrives with close attention to lighting, plant and rock selection

Shown above * Aquascaping thrives with close attention to lighting, plant and rock selection




Plants & Plant Weights

There’s a variety of plants available for planted tanks, mimicking the flora you’d use for landscaping a non-aquatic terrarium. Some plants are mossy, others grassy. Some look like ferns, and others still grow tall and flower at the surface. To keep your plants grounded to the desired spot, be sure to hold them down with plant weights wrapped around the roots. LiveAquaria offers several freshwater plants, including curated packages for immediate gratification.

Decorative Stone/Rocks

Rocks are among the best opportunities to incorporate color into the design of your underwater terrarium. Use several rocks of varying sizes to build up a rock garden of sorts. Large crystals will add a glassy shimmer to your tank, but will require an occasional scrub to maintain their original gleam. Non-porous rocks require even less cleaning, repelling algae build up.


A branching piece of wood can take a tank’s design elements in many directions. Have fun with your driftwood pieces, placing them at angles to achieve a most eye-catching portrait. If using real wood, be sure to soak the piece for several days (sometimes two weeks or more) before placing in the tank, as the wood will brown the tank water. Though harmless to the plants and fish, brown water will require more water changes (i.e. more maintenance) until the color has worked its way out of the wood.


Freshwater fish are plentiful, and can provide a mesmerizing point of interest with your tank. Keep things low maintenance by adding just a handful of fish types. A school of fish works best for underwater terrariums, ensuring there’s almost always some action going on in the tank. Other animals including frogs, snails, shrimp, lobsters and clams can also be added to your waterscape. LiveAquaria has a plethora of freshwater creatures available for purchase.


Automate It


A smart tank is one that doesn’t take up too much time for maintenance. Keep your underwater terrarium looking its best with minimal effort by automating it. Incorporating a bit of smart tech will also allow you to leave the tank for days at a time (spring vacation, here we come!).

Lights are on a timer

Optimize your underwater terrarium’s light exposure by automating with a timer. Now fish will wake up and go to bed when you do, without having to remember to turn the aquarium lights on or off. I recommend the Ecoxotic LED controller for light automation.

A simpler aquascape showcased in a modern cube, rimless tank

Shown above * A simpler aquascape showcased in a modern cube, rimless tank


Taking a four-day road trip? Make sure your fish and plants don’t starve with an automated fish feeder. Eheim makes a range of fish feeders to suit a range of needs.

Backup Power

In the event your power goes out while you’re away, backup power can ensure your underwater terrarium air pump and thermostat continue to maintain an optimal environment. In most instances a backup battery pack for the air pump will suffice, but to keep the temperature levels copasetic a backup power supply, such as those used for desktop computers, will do the trick.

Bonus: Watch While You’re Away

Want to see what’s going on in your fish tank while traveling? A Wi-Fi enabled camera can offer remote access. The Homeboy camera is a great choice thanks to its wireless design and long-life battery.


Local Resources : San Antonio, TX


All of the design elements included in my underwater terrarium (feature image) were purchased locally. Here’s a resource list local to my current city, San Antonio, TX.



Plants & Plant Weights

Aquarium Adventures (Northwest)

Decorative Stone/Rocks

Alamo Aquatic (Leon Valley)

Aquarium Adventures


Alamo Aquatic


Aquarium Adventures

  • 1 betta (yes, he gets along with the fancy guppies)
  • 2 fancy guppies
  • 6 tetras
  • 2 mollies
  • 1 albino catfish (He’s not always the prettiest to look at, but he cleans every inch of the tank. His quick and constant work will always give you a show.)



Feature image by The Clever Life