How To: 5 Gallon Aquascape with a Cave (No Filter, No CO2)

by Kevin

Cave aquascape in 5 gallon aquarium.

The purpose of this article is to show you, step by step, how to create a captivating cave aquascape in a 5 gallon tank.

Caves have an aura of mystery.

This aquascape tutorial seeks to convey that sense of mystery by using a grow light to illuminate the inner depths of the cave with a soft orange glow.

5 gallon aquascape.

5 gallon tanks actually make ideal canvases for aquascaping because fewer plants, stones, and materials are needed create a complete aquascape.

The downside of a 5 gallon aquarium is less room for fish, but that doesn’t mean your tank can’t be full of life.

My own tank is full of blue cherry shrimp, which produce tiny amounts of waste compared to fish and, therefore, can be kept in relatively large groups in a 5 gallon.

Blue cherry shrimp in 5 gallon tank.
Blue cherry shrimp scavenging for algae.

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How to Create a 5 Gallon Cave Aquascape

This aquascape tutorial is composed of 9 steps:

1) Place Tank on Appropriate Surface

2) Fill Two Mesh Filter Bags with Substrate

3) Select and Position Stone Hardscape

4) Add Aquarium Plants

5) Add White Sand or Gravel for Contrast

6) Make Sure Stones are Stable and Visually Pleasing

7) Cover Aquascape with Plastic

8) Add Water

9) Add an LED Light

For those who enjoy watching a tutorial, I’ve created a video of how to setup a 5 gallon cave aquascape:

And, for those who enjoy a more detailed breakdown of each step, keep reading.

Step 1: Place Tank on an Appropriate Surface

Rimless tank on wooden table.

Fresh water weighs about 8.34 pounds per gallon (3.78 kilograms), so a 5 gallon tank filled to the top is going to weigh close to 42 pounds (19 kilograms).

If you include substrate/gravel, rocks, and plants, that tank is likely to weigh well over 60 pounds.

So, before setting up your 5 gallon aquascape, find a table, desk, or stand that comfortably supports the weight of your tank.

In general, avoid placing your tank in a spot that receives direct sunlight.

Algae are experts at utilizing sunlight and will quickly explode if given consistent sunlight.

Picking a spot near an electrical outlet is helpful, as heater and aquarium light cords tend to be short in length.

Step 2: Fill Two Mesh Filter Bags with Substrate

Mesh filter bags filled with substrate or gravel.

With your tank situated on a sturdy surface, take two mesh filter bags and fill them with substrate, gravel, or filter media.

The goal is to create an incline, which will add depth and interest to your aquascape.

Cover the filled mesh bags with additional substrate, using your hands to smooth out the slope into something that resembles a 45 degree angle.

Even in a small contained space, like a 5 gallon tank, the gradient in height created by this slope will dramatically alter the visual appeal of your tank, adding depth and interest.

Step 3: Select and Arrange Your Stones

Seiryu stones in 5 gallon aquascape.

If your goal is to create a cave, look for 2-4 chunky stones that have at least 1 flat side.

These will serve as the posts for the topmost rock to sit on.

In my aquascape, I did not use glue to secure the rocks, instead I selected specific stones that were stable enough to rest on top of each other.

But, for taller scapes or when using stones with irregular shapes, using super glue to bond your stones together is a smart idea.

Rocks in unstable aquascapes may tumble over during a water change, possibly causing the aquarium to shatter.

Step 4: Add Aquarium Plants

Adding aquarium plants to an aquascape.

Once your stones are positioned, begin adding aquarium plants.

Plants with long leaves, like Java fern, work well in the back of the tank and shorter, slower growing plants, like Anubias, are ideal for the midground region of the tank.

Keeping the front area of your tank clear helps create a sense of depth, as the eye moves toward the back of the tank.

Carpeting plants, like Monte Carlo (Micranthemum), also help create a sense of scale and depth, but tend to require additional maintenance to maintain that grassy field type look.

In this setup, I opted for easier plants:

1. Anubias barteri

2. Java fern

3. Java moss

4. Susswassertang

5. Cryptocoryne wendtii green

These plants grow well under low to medium light and thrive without CO2 or fertilizer.

In my setup, I use Eco Complete substrate, which contains nutrients that provide food for the plants.

Step 5: Add White Sand or Gravel for Contrast

White sand added to an aquascape.

Instead of carpeting plants, an effective way to add contrast and interest to the front of your 5 gallon scape is using a different colored substrate/gravel.

In this setup, my primary substrate is Eco Complete, which is dark, and by adding a light colored substrate, like cichlid sand, the aquascape immediately gains visual appeal.

To my eyes, the white cichlid sand in the foreground, creates a beach cave feeling.

Other types and colors of sand, gravel, and even botanicals (like catappa leaves and alder cones) could be used to invoke other biomes, like a forest floor.

Step 6: Stabilize Stones and Add Visual Appeal

Creating a cave aquascape with Seiryu stones.

This step seems insignificant at first, but taking the time to place your stones in a way that brings joy to your eyes is important.

If you use super glue to hold your stones together, this step is especially important because rearranging the aquascape later may require separating already glued together stones.

Making sure your stones are securely resting on top of each other is also crucial.

If one topples over during a water change, the tank could crack.

In this 5 gallon aquascape, I made sure that each Seiryu stone was stable before piling another one on top.

Step 7: Cover Aquascape with Plastic

Using a plastic bag to protect an aquascape.

Before dumping water into your tank, place a plastic bag or some bubble wrap on top of your aquascape.

This will prevent your substrate from shifting and toppling rocks or uprooting plants as water is added.

Step 8: Add Water

Adding water to 5 gallon aquascape.

Adding water slowly is key.

Dechlorinated tap water is perfectly adequate for an aquascape like this (unless you are keeping sensitive species).

The water dechlorinator I use is API Tap Water Conditioner, but almost any commercial dechlorinator designed for aquariums will work.

I typically do a weekly water change of about 30%, and a larger 60% water change once a month.

Step 9: Add an LED Light and Heater

5 gallon aquascape aquarium light.

I used a small Aqueon heater for this tank, which worked well for a few months, but almost any 50 watt heater will work and the one I am currently using is below:

As for the light, it no longer appears to be available, but an excellent alternative is this Hygger, which comes with allows you to control its brightness:

LED light technology has advanced immensely, and now even “cheap” LED aquarium lights grow plants with relative ease.

How to Create an Orange Glow in Your Cave Aquascape

While not essential to the aquascape, placing a small grow light, or warm toned light, behind your tank will create a sunset effect.

The specific light I used is this one:

Grow light for cave aquascape.

If your tank is on display in your living room or somewhere that gets foot traffic, this glow effect will turn heads.


The limited space of a 5 gallon tank makes aquascaping a challenge.

But, these space constraints can also be an advantage.

The placement of each rock and each plant requires deliberate thought in such a confined space, and so the end result is often more intricate than an aquascape in a larger tank.

Maintenance is also much easier in small tank.

One 5 gallon bucket is all you would need to perform a 100% water change.

But, the size of a 5 gallon also limits the number of fish you can have, and we all like having lots of fish.

If you are interested in which aquarium fish are best suited to life in a 5 gallon, check out my article on the best fish for a 5 gallon tank.

And, if you want to learn more about setting up planted aquariums, check out my guide on planted fish tanks.

Also, check out my article on the best algae eaters for freshwater tanks, every aquarist battles algae at some point.

I hope you found inspiration to create your own 5 gallon cave aquascape.

As always, stay zen.