How To Use Seiryu Stone In Your Aquarium

How To Use Seiryu Stone In Your Aquarium

Creating the perfect aquascape for your aquarium is an art form. Providing an environment for your aquarium inhabitants to flourish that is also aesthetically pleasing is a challenging endeavor. One of the main reasons why Seiryu Stones have been so popular in aquascaping is because they are as beautiful as it gets.

If you want to create the ultimate hardscape for your fish, you’ve come to the right spot. We’re going to discuss everything you need to know about this Japanese trend and why so many aquarists gravitate towards Seiryu Stone. 

How To Use Seiryu Stone In Your Aquarium

What is Seiryu Stone?

The Seiryu Stone is named after a deity because of its majestic shades of deep blue and grey with subtle white touches. The deity is called the Blue Dragon and is one of the Four Symbols used traditionally to represent Chinese Constellations.

The Seiryu Stone, also known as The Thousand Layer Stone, is derived from carbonated limestone and fine lines of calcite running like veins through the layers. The stone is a heavy rock to work with, and the Germans call it Mini Landschaft (miniature landscape) because of its texture complexity. 

This stone became popular around the world thanks to the work of Takashi Amano. In case you are not familiar with him, he is the father of the Iwagumi (and Amano) styles for aquascaping. “Iwagumi” stands for “rock formation” in Japanese, and his take on it intends to mimic nature by utilizing non-symmetrical designs.

Advantages of Aquascaping with Seiryu Stone

Takashi Amano used Seiryu Stone for his minimalistic, Iwagumi designs primarily because of the stone’s natural beauty. The dark blue seems like an entire universe mixing with the fine white lines and subtle gray touches.

Besides its aesthetic beauty, this stone provides a ton of benefits for your aquarium.

Dramatic Contrast

The deep, complex colors of the Seiryu Stone make a dramatic contrast against the plants and fish you have in your aquarium. The lighting in your tank creates various colors within each stone, resulting in a 3-D effect in your fish tank. 

Create Mountain Effect

The grain and external fractures within the Seiryu Stone create a mountain effect. You can easily create a full landscape with just a handful of stones and a few green leaves with some expertise. Just make sure you follow Amano’s teachings and mimic nature’s non-symmetrical designs.

Hiding Places

Sometimes, fish in aquariums can feel threatened or shy, and rocks can be the perfect hideout for them. When your fish feel safe inside their habitat, they might even lay some eggs in those stones. Providing a safe and sound habitat for your fish will reduce stress for your fish aquarium. 

Algae Growth

Rocks in aquariums can reduce the levels of nitrate or ammonia in your tank. This provides a great environment for algae growth. This is beneficial for your aquarium inhabitants that feed on algae. 

How do you Clean a Seiryu Stone?

There are several ways of cleaning a Seiryu Stone before submerging it into the water. Let’s take a look at the most common ones:


Most users recommend boiling the Seiryu stone for at least half an hour to clean it thoroughly before it hits the aquarium.

Wash it Underwater 

Like you would wash any other element, place the stone underwater and give it a thorough wash for at least ten minutes. Make sure you do not see any debris before you submerge it. If needed, use a toothbrush to clean the tiny holes in the sides as well.

Use Muriatic Acid 

The muriatic acid will take care of any kind of impurity that the Sriryu Stone might have. Fill a bucket with the acid and drop the stone in there for half an hour. Use eye and hand protection since muriatic acid is highly toxic. 

Next, use pliers to remove the stone from the bucket and submerge it into the water for another half an hour. The second step should dilute any acid still in the stone. Beware because this method will darken the stone to be almost black.

How to Test Sieryu Stone’s Acidity or Alkalinity?

Can the rocks we add as a decor to our aquariums change the water composition? The answer to that question is an absolute yes. As you might know, the pH of the water your fish swim in is essential for their wellbeing. Furthermore, different kinds of fish require different pH levels.

Depending on the type of inhabitant you have in your aquarium, the water in which they swim will have certain requirements. These requirements are usually to match those of their natural habitat. Thus, if your fish require more alkaline or acid water than the one available in your area, you can modify the one in your aquarium by adding the right type of stones.

Some stones are inert, which means that they do not alter the GH, pH, KH, or nitrate and nitrite levels in your aquarium. Rainbow rocks are a good example of this phenomenon.

The Seiryu Stone is limestone-based, and thus, it is not inert. You can expect the Seiryu Stone to change the composition of the water. 

Here are the common methods to test Sieryu Stone’s acidity or alkalinity levels. 

Acid Test

There are several ways of performing an acid test on the stones before they go inside your aquarium. The most common method is to use regular concentrated white vinegar that you can easily get at any local store. An alternative method is using chemistry acid kits. 

Step 1: Clean the Stone

Wash the stone thoroughly and look out for any debris. Once it is clean, you need to let it dry to the point there is no visible water on the surface. 

Step 2: Apply the Acid

Once the stone is completely dry and clean, drop a few drops of acid on top of the surface. Make sure you check the stone’s composition and if you notice a different material in a certain area, drop another bit of acid there. Sometimes, stones have a mixed composition and need to be checked in more than one spot.

Step 3: Check for a Reaction

If you see sizzling or bubbles appearing on the surface of the stone where you dropped the vinegar or acid, then you can be certain that the stone is alkaline. In other words, adding this stone to your aquarium will make the alkaline levels of the water go up. 

Soak Test

The second way to check on your stones’ acidity or alkalinity is by conduction a soak test. Since you’re interested in knowing the water’s chemical reaction surrounding the stones, the second method’s idea is to soak them and check that reaction.

Step 1: Fill a Bucket with Water

Get a bucket and clean it thoroughly to make sure no other agents in the bucket. The water you fill it with should be the same you will use in your aquarium so you can check the exact result you will have with it.

Step 2: Measure the Water

Using measuring kits, measure all the indicators the same way you would in your aquarium. These include pH, ammonia, and hardness. You can always buy a master kit containing all indicators. Note down all indicators before submerging the stones into the water.

Step 3: Soak the Stones

Soak the stones inside the bucket and leave them there for an entire week. After a week, you need to perform the same tests you did before the stones were placed in the water. Write down the values and compare the differences. If any value changes drastically, you can expect the same thing to happen to your aquarium.

Managing Seiryu Stone effects on Water Chemistry

Seiryu Stone has a strong effect on the water of the aquarium. Furthermore, if you overlook this step and don’t take proper care of the water in your fish tank, you can severely harm or even kill all life in it. 

After sinking the Seiryu Stone, to create a beautiful underwater hardscape, you need to neutralize its effects on the water. The calcium and carbonate in the stones impact the concentration of each mineral in the water. As a result, GH and KH of the aquarium are drastically modified.

Although you might have some fish that will be initially happy in such an environment, such as Lake Cichlids and Livebearers, the effects could be harmful in the long run. Let’s take a look at two straightforward methods you can implement to keep your animals happy and healthy, and their environment breathtakingly beautiful.

Frequent Water Changes

Once the Seiryu Stone is sunken, it will continue to release calcium and carbonate to the water intermittently. If you don’t change the water, it will become too much for your aquarium inhabitants. The best antidote for this is to change the water, so the concentration levels drop.

Changing too much water at once could increase the aquarium water’s hardness drastically, harming the inhabitants. You want to perform periodic small water changes (three to four times a week) to avoid any negative results. 

Acid Buffers

There are three possible states for the pH in the water: alkaline, neutral, or acid. Since the Seiryu Stone turns your water into a more alkaline solution, you need to add acidity to it; thus, you need an acid buffer. Some of the best options in the market are: 


Besides being a great aesthetic addition to your aquascape and a great complimentary item to the Seiryu Stone, driftwood will help counteract the stones’ alkaline effect.

ADA Aquasoil & Peat Moss 

Acidic substrates like ADA Aquasoil (Aqua Design Amano, the first ones to popularize the Seiryu Stones) are specially designed to work with minimalist Iwagumi aquascapes. Thus, they make the aquarium water a good habitat for species like cherry shrimp, cardinal tetras, and other likely inhabitants. 

On the other hand, these buffers are made of decomposed leaf mulch, rich in humic acid (because of the decomposition of the dead organic matter), which means you should change the water more often.

Carbon Dioxide 

Also known as CO2, this gas turns into acid when it dissolves into the water, pushing the water back to a neutral pH. Injecting carbon dioxide directly into aquascapes can help manage acidic levels.

How to Break Seiryu Stone

Breaking a Seiryu Stone is not an easy procedure. You’ll need some specific tools, a lot of patience, and some luck, but results can be amazing. 

Before we start, it is paramount that you use eye protection when attempting any of these techniques. Plus, you should also wear hand protection if available. Let’s take a look at some common methods:

The Hammer & Towel Technique

This is a straightforward technique with easy-to-find tools. All you need to do is wrap your Seiryu Stone in the towel and then hit it (gently) with the hammer. The result should be a boulder and some smaller pieces conveniently contained within the towel.

The Hammer & Chisel Technique 

If you have in mind a precise cut you wish to make for your stone, you can use a hammer and a chisel to cut at the exact location. Bear in mind pieces will fly around, so do it in a controlled space.

The “Oops I Dropped It” Technique 

For this method, be sure to set up a safe place for pieces that will fly around. This method can cause damage to floor tiles, so outdoors on a tarp would be ideal. Once your space is set up, drop the stone from your hand, and voila, you’ve broken it into pieces. 

The Diamond-Bladed Saw Technique 

Many types of diamond blades can be used to cut material such as stone, concrete, asphalt, bricks, glass, ceramics, gemstones, etc. A diamond blade will not give Seiryu Stone the most natural look, but it is best for a clean and quick cut. If you know exactly what you are going for and need precision to achieve it, this is the perfect method.

Where Can I Buy Seiryu Stone?

The Japanese government has forbidden the expiration of Seiryu Stone outside of Japan since 2008. This means unless you live in Japan, it will be near impossible to get this stone. Beware of retailers online claiming to be selling Seiryu Stone. It is most likely, not the real thing. 

If you do find this stone available at highly-specialized aquarium retailers, bear in mind you will pay a hefty price for them.

There are some great alternatives to Seiryu Stone for your aquarium if you are trying to get a similar aesthetic look.

Molded Stone

Due to Seiryu Stone’s popularity and its lack of availability, many retailers now specialize in molded stone. These stones are made from resin molds and mimic Seiryu Stone in their appearance. They are safe for your fish, and they do not alter the water chemistry of your tank.   

Ryouh Stones

Most retailers claiming to sell Seiryu Stones outside of Japan are actually selling Ryuoh Stones. Ryouh Stones are commonly confused for Seiryu Stones based on their striking resemblance. The Ryouh Stone is more slate grey and does not produce as much contrast against the white veins as Seiryu Stone.  

Due to the similarity, Ryouh Stones are a great alternative to the Seiryu Stone for your aquarium. This stone is easier to access and still provides an aesthetically pleasing look for your fish tank.  

Final Thoughts

Seiryu stones can be the element your aquascape needed to reach the next level. It is challenging to find any other stone that resembles its complex beauty and 3D like appearance. If you can manage to create the right water environment for your aquarium animals, you’ll be as close to creating a living work of art as it gets.

Looking for tips about aquarium maintenance? Head over to our Aquarium Maintenance & Repair section to see more.

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