Grow Aquatic Houseplants in a Mini-Aquascape (with Shrimp)
An aquascape is a small aquatic ecosystem of well-chosen plants, brackish water, mineral sand, and sea animals assembled in a glass container—it's like a terrarium but water-based instead of soil-based. More complex ones offer a variety of plants and fish as well as a filtration system.
These instructions are for a simple self-contained aquascape containing plants, algae, and small shrimp. Properly maintained, this habitat can sustain life a surprisingly long time—about ten years! I settled on this design after experimenting with several different aquascape features, and I’ve found this version offers just the right balance of adaptability, longevity, and creative control.
Please read the entire guide before starting. Using quality ingredients is important—avoid irresponsible suppliers so you don’t wind up with contaminants in your habitat. Also keep in mind that anything else you add to your aquascape needs to be safe for its new environment—watch out for anything that is porous or organic in nature, like unsealed clay decorations. Opae’ula shrimp are known to live up to 20 years in their natural environment, but most small shrimp live 1 to 2 years. You may use different tiny shrimp (such as red rock or ghost shrimp), but you’ll need to make sure the water salinity, container size, etc., meet their needs.
- Small glass container (500–2,000 ml)
- Seawater or marine salt
- Distilled water
- Barnacles, lava rock, ornaments, or shells
- Refractometer (to measure water salinity)
- Waterweed and/or marimo balls
- Opae’ula (Hawaiian red shrimp)
- Argonite sand (small bag)
- Large spoon
- Chopsticks or large tweezers
The Saline Factor
This aquascape involves brackish water and euryhaline organisms, which are able to adapt to a wide range of salinities. (The word "euryhaline" derives from Greek eurus, "wide," and halinos, "of salt.") They have the capacity to adjust to external salinity, say, from freshwater to very low salinity. Still, even though these organisms can survive in less than optimal conditions, they will live longer in a well-regulated habitat.
The first step in creating ideal conditions for your plants and shrimp is to establish the correct water quality and salinity. Brackish, or briny, water is more saline than freshwater but less so than seawater. In the natural world, it may result from mixing seawater with freshwater, as in estuaries, or it may occur in some fossil aquifers. Certain human activities can also produce brackish water. For instance, coastal marshland may be flooded to produce brackish pools for prawn farming.
You can measure salinity with a refractometer, a small scope that uses specific gravity to determine the amount of dissolved salts. Measuring salinity on a semiregular basis is crucial to maintain the ideal environment for your marine inhabitants.
Pure water has a specific gravity (SG) of 1.000. Ideal salinity for our project is SG 1.006–1.008, but anything in the SG 1.005–1.010 range will work. This is a little less salty than typical saltwater fish tanks, generally SG 1.021–1.026.
There are two ways to make brackish water. The first is by purchasing seawater at your local aquarium shop and slowly adding it to distilled water until you get the desired salinity. The second is by adding marine salt to distilled water, mixing well, and letting it sit for several days. The water should be room temperature.
The Rest of the Ecosystem: What Does What?
Aragonite SandAragonite is a naturally occurring form of calcium carbonate created by mineral precipitation from marine and freshwater environments. It provides the materials (elements such as calcium and magnesium) necessary for much aquatic life, produces oxygen (and other gases), reduces nitrate buildup, and helps maintain the pH balance of the water. You will need enough to make a one-inch layer at the bottom of your vessel.
OrganismsWaterweed or Anarcharis (Elodea species)
Elodea is a genus of six species of aquatic plants native to the Americas and first described in 1803. The genus was once called Anarcharis, and it's sometimes sold under that name. It typically lives in freshwater, though it tolerates brackish water, and is widely used as aquarium vegetation.
American waterweed (Elodea canadensis) lives almost entirely underwater and may be rooted in the shallows along the shoreline or float loose on the surface of nutrient-rich freshwater ponds and lakes, as well as in brackish coastal waters. It is found throughout temperate North America, where it is one of the most common aquatic plants.Marimo or Lake Ball (Aegagropila linnaei)
Marimo (meaning "ball seaweed" in Japanese), sometimes called lake ball or moss ball, is actually a species of filamentous green alga that sometimes combines to form a ball. Colonies of them are occasionally found in freshwater lakes in the Northern Hemisphere. You can use waterweed or marimo or both in your aquascape.
This Hawaiian species, also called Hawaiian red shrimp or volcano shrimp, is typically found in brackish pools near the sea. It rarely grows longer than 1/2 inch.
You can purchase most of these materials at your local aquarium supply store, but you may need to special order the shrimp from a Hawaiian distributor. Search online to find one.
Putting It All Together
Step one: Make the water
Review the instructions above. Remember, if you are using marine salt, you will need to start it several days in advance. Keep your water in a separate container until the other materials are put into place.
Step two: Add sand to your container
You won’t need to use too much, just about an inch.
Step three: Add your décor and plants
Set on the sand your choice of barnacles, lava rocks, shells, or even a cute aquarium-approved treasure chest. Plants go in now too! You can tuck the waterweed into the sand, or perhaps in a shell for a more unique look. If you are using marimo, now is the time to place it.
Step four: Add water
To avoid clouding the water, hold the vessel at an angle and add the water slowly down the side, as if you were pouring a beer. Use the chopsticks or tweezers to adjust your décor. Let the water settle and clear a few minutes before adding your shrimp.
Step five: Add shrimp
Opae’ula for you-la! These shrimp are tiny but you don’t want to use too many. Ten per gallon is a reasonable amount, so the smaller the container, the fewer shrimp. Gently transfer them into their new environment with a large spoon (not a net)—it’s gentler on these delicate creatures.
Step six: Enjoy
Gaze lovingly at your new aquascape. You will not need to feed the shrimp. They will feed on the algae naturally produced in the aquascape. The shrimps' waste adds nutrients to the water for the plant life. Occasionally check the water salinity, but it should do quite well for many years with just some occasional love (adding water, minor pruning, etc.).
The water may be a bit cloudy for the first few days. This is normal. It should clear and correct itself.
The shrimp may appear shy until they acclimate. The ecosystem can take up to two weeks to settle and balance, and it’s normal for the shrimp to hide until they feel safe. If they’re alive, you’re doing great. Don’t worry.
More: Take a Miniature Aquascape workshop at Brooklyn Botanic Garden in January.
If you see excess algae growing on the glass, reduce the light exposure by moving or covering your aquascape until the algae diminishes. If it’s not better after a week, you should prune or remove some plants.
Location and Lighting
Your aquascape will thrive at room temperature: 65°F–85°F. Safe gradual temperature fluctuation is within 10°F to 15°F. Keep the aquascape out of drafty areas where temperatures may vary drastically.
Place your aquascape in indirect sunlight, part shade, shade, or a moderate amount of fluorescent light. A windowless bathroom won’t work, nor will a sunlit windowsill.
Do not keep your aquascape in a hot kitchen or on any electrical appliance. In addition to heat and light fluctuations, the shrimp can be sensitive to vibration. Don’t shake, vibrate, or play loud music next to your aquascape.
Use only distilled water to replace water lost to evaporation. If you see salt around the outer rim, just replace it back into the environment by gently tilting the container. Always use chopsticks or clean hands when adjusting your aquascape to prevent contaminants from altering the water chemistry.