How to Set Up an Iwagumi Aquarium

Iwagumi Aquascape Stones main

Today I would really like to discuss one of the most interesting and deeply historical topics. In fact, I would like to tell you about the process of the creation of a Japanese stone garden in the aquarium. I’m more than sure that many of you are already aware of the Iwagumi term, especially if you are a frequent user of various forums and portals on the web related to the aquaristics.

Iwagumi is a unique composition of stones (or the so-called ‘garden of stones’). In addition, Iwagumi is a Japanese word. It’s worth noting that Iwa means “stone”, while Gumi means “arrangement”. Obviously, Iwagumi is a technique that involves the placement of two or more stones in order to create an attractive composition in the aquarium. Another term used to describe this aquascaping trend is Ishigumi.

Iwagumi is one of the most complex styles of aquascaping. In fact, one has to deal with a whole set of rules, recommendations, and tips. The key task of the aquarian is to bring some ‘life’ to the stones, thus making them show the entire space, which can be quite difficult for a novice. The good news is the fact that this style offers a simplified version consisting of only three stones.

History of Iwagumi Aquascaping

Takashi Amano is considered the founder and the pioneer of this trend in the field of aquaristics. He became incredibly popular and well-known all around the world. It’s worth noting that he used Iwagumi stones in a natural aquarium for the first time in 1985. In order to create his composition, he used several river stones refined by the waves and a plant called Echinodorus tenellus. He managed to use an incredibly creative approach and had stratospheric success.

Since then, Takashi Amano created and offered a lot of different variations of arrangements of Iwagumi stones for the public audience. It stands to mention that from the moment of the creation of the first composition in this style and to the present time, the attractiveness and charm of this trend in the world aquascaping are only growing.

Takashi Amano - first Iwagumi Aquascaping 1991
Takashi Amano – first Iwagumi Aquascaping 1991

Iwagumi Styles and Basic Principles

If you decided to use Iwagumi as the main style for your home or office aquarium, you need to know that it offers several different variations hidden within one style. Before making any changes, you need to know that each of these variations offers different positioning, directions, shapes, and numbers of stones. At the current moment, there are about six main styles of aquarium design within the Iwagumi style.

Kindly note the following: There are a huge number of drawings, schemes, and rules, which can be found in the main book of the Japanese garden called Sakuteiki. One shall follow all of them in order to create a proper and attractive composition of the stones.

Here are the basic principles of Iwagumi style:

  1. Stones are the true bones of the Japanese garden. If one is able to place the stones in the right way, the rest of the garden will appear without any help.
  2. First of all, one needs to place the stones, following with the trees and grass. The key idea is to use the stones to create the landscape of the future composition. One should avoid using plants to create it.

Kindly note the following: The same principle shall be applied in the case of the Nature Aquarium and driftwood placement. 

Style 1: Fossilized Wood

Iwagumi aquascape - Style 1 Fossilized woodThis unique style is based on the compositions made from fossilized wood. For the first time in history, this type of composition featuring the Glossostigma plant was shown to the public audience in 1991 and was a huge success.

It’s worth noting that this variation of the style never became truly popular due to the ability of these stones to greatly increase the water hardness. At the same time, this style is considered to be the “original” one. In addition, one can easily find new and new works by talented people from all over the world, who want to show and highlight the unique texture of fossilized wood.

Style 2: Sanzon

Iwagumi aquascape - Style 2 SanzonThe Sanzon style is based on a symbol from Buddhism. The key feature of this style is a triad or a triangular arrangement of stones. The Buddha (the main Oyaishi stone) is located in the center of it, while his main servants (secondary Fukuseki stones) and all the others (auxiliary Soeishi stones) are located right next to it.

Here’s the most important rule of this incredible style:

  • Iwagumi style focul point Golden ruleThe main stone must be placed strictly at the point of the Golden ratio (read more about some rules of aquascaping here).
  • All other stones are used to form triangles with it.
  • The main stone has to be larger and necessarily higher than the second stone, while the second stone has to be higher than the third. One needs to remember that the Iwagumi style is used to represent a meadow, a lawn or a field.
  • Iwagumi style focul point Golden rule“The largest stone is placed a bit in the front, the second largest stone has to be located to the right of it and a bit behind. The smallest stone is placed to the left of it and a bit behind. One needs to keep the proportions in such a way to make the aspect ratio of 2:3 of the resulting triangle from left to right from the front. Three imaginary lines between the centers of the stones should form a triangle. One needs to know that the shape of the stones becomes irrelevant if you decide to use this unique technique!” (Takashi Amano)
    Important note: You can put the stones in the same way, but using a mirrored structure, i.e. the largest stone has to be located in the background.
  • If more than three stones are used to create the foundation of the composition, then the next three stones are placed according to the same principle, but on a triangle of a larger or smaller size; one shall use a different shape, and shift the second triangle relatively to the first one.

Important note: When placing stones of different sizes, try to take their texture into account. E.g., try to make sure that all the cracks are located in the same direction. In addition, always use some soil to fix the base of the stones. This will create an impression that the group of stones is nothing but a whole stone. This is an important technique if you don’t have stones of the right size. You need to remember that the fundamental rule of the Iwagumi style is to create an impression of balance and continuity. 

Style 3: Sand Sanzon

Iwagumi aquascape - Style 3 Sand Sanzon
Takashi Amano. 2008

This unique style repeats all the principles of Sanzon; however, the key difference is hidden in the fact that a special atmosphere is created with the help of decorative sands put in the front.

Sand highlights the aquascape makes decorative elements more contrasting and creates additional depth in the perception of the composition. In this case, sand is used to create the impression of the sea coast or a riverbank. 

Style 4: Rays

Iwagumi aquascape - Style 4 RaysThis unique style is characterized by sharp and thin stones, which form solid sun rays sticking out in different directions. It’s very important to find the harmony of the stones so that the whole composition looks balanced. Since the top of the stones is always directed upwards, the shape of the top plays a huge role in the balance of the entire composition.

The apparent simplicity of this style is very deceptive. Sharp stones are unstable and you need to have the insight to leave the impression of a vigorous temper of nature. There’s no chance to use different kinds of supports and other elements to make the entire composition more stable. Perhaps this is why the style is not truly popular. 

Style 5: Mountains

Iwagumi aquascape - Style 5 MountainsUnlike many other Iwagumi styles, in this case, the stones are arranged in a natural way, thus imitating the natural location of stones, mountain ranges, peaks or reefs.

In this case, the roles of the objects are blurred. Stones are not used on their own to create the composition. All elements create a strong stream of power. The design starts right out of the ground. The free space is filled with soil and planted with grass.
This design is characterized by a horizontal arrangement of stones and is more suitable for long panoramic aquariums. 

Style 6: Twins

Iwagumi aquascape - Style 6 TwinsThis variety of Iwagumi style can be easily distinguished as an independent one. It’s considered more expressive and shocking, although it still follows the basic principles of Iwagumi.

This style is characterized by the location of two massive, often equivalent (main) stones in the focal point.

Sanzon Iwagumi (additional style)

In general, one needs to use at least five stones to implement all the basic principles of Iwagumi style. At the same time, in some cases, you can create a composition with a smaller number. This variation of the style consists of only three stones (main, secondary and auxiliary).

Classification and Names of Stones in Iwagumi

The design and maintenance of an aquarium in the Iwagumi style require certain knowledge and skills. Moreover, it’s important not only to place the stones according to the set of certain rules, so that the composition turns out to be balanced and attractive but also to choose them in a right way. 

Iwagumi Aquascape Stones (Classification and names of stones in Iwagumi)


This is the main stone and the most significant and the most important in Iwagumi. This is the largest and the most beautiful stone available. The height of the main stone should be approximately two-thirds of the height of the aquarium.

One shall use this stone as the first step to create the unique design and style of the aquarium. Oyaishi is always used as the center element using the golden section or focal point rules. In the perfect situation, the main stone has to have two-thirds of the length, width, and height of the aquarium. It has to be located at an angle to the flow of water, as in the riverbed.


This is the secondary stone. This is the second-largest stone located to the right or left of the main stone. It serves to create a visual balance of the resulting stone composition. In order to find the secondary stone, you need to choose a stone that has a similar shape and texture as the main one.


This is the auxiliary stone. This stone is smaller in size than the secondary stone. In addition, it’s located right next to the main and to the secondary stones.

The auxiliary stone plays an important role, emphasizing the massiveness and significance of the main stone. The main goal is to highlight the beauty of the first two stones.


This is the auxiliary stone. The name of the stone means “thrown stone” in Japanese. It serves to ensure the balance and harmony of the entire structure. These are small pieces of stones, which can’t be placed separately from the main Iwagumi composition. Sometimes they are completely covered by plants. The presence of such stones gives completeness and finishedness to the composition. With the help of decorative stones, the composition becomes more harmonious and refined.

The height of the stones has a strict hierarchy according to its role in Iwagumi.

Interesting fact: Those of you, who always think about the importance of the names, will be happy to know that by placing stones in a certain position, one should symbolize the admiration of the Buddha. 

Main Rules for Stones Placing by Takashi Amano

  1. Never put an even number of stones. You can only put an odd number of stones, i.e. 3, 5 or 7.

Takashi Amano emphasized that symmetry is not typical for natural landscapes. He always said that it occurs every time when a person tried to participate in the process of creation. The odd number of stones makes the process of creating a natural landscape easier since it is difficult to create symmetry from an odd number of elements. Thus, the odd number will make it possible to form a natural composition even for beginners.

  1. Never put stones of the same size and shape.
  2. Do not use stones of different colors or from different areas in the same aquarium.
  3. Never place rocks and driftwood in unstable and unnatural positions. The natural look should be the foundation of any composition in aquascaping.
  4. Never put stones in a row; by doing so you will simply destroy all the volume of the entire composition.

Key Rules for Groups of Stones by Takashi Amano

  1. Stones are always placed in groups. There may be several groups in the aquarium.
  2. Only one of the five main types of stones can be used in each group of stones (except the third item). The remaining stones of each group should have a different shape from the main one and simply complement it.
  3. One can use 2-3 stones of the five main types within a group, but they have to be slightly different in size. Those are Male and Female stones.
  4. Groups of stones shall consist of two or three pieces of the same basic type, which can be combined into a large composition to create a larger focal point.
  5. Never use stones in the following cases:
  • If they are damaged or have been cut off;
  • If the top of the stone is larger than the base (except for arched and branching stones);
  • Never put vertical stones horizontally and vice versa;
  • If the stones have different structure and type (this will affect the continuity and harmony of the entire composition);
  • If the stones have a different structure; e.g., never mix stones refined by the water (coastal) with the stones with sharp edges (from mountains);
  • Never put the stones in such a way to locate the symmetry axis of the stone at a right angle to the walls of the aquarium.

5 Types of Main Stones in Iwagumi

  1. Low vertical (Soul and Reishoseki stones). The base is much wider than the tapering tip. This is one of the most popular stones.
  2. Tall vertical (Body, Taidoseki). This is the vertical stone with the base, which is a bit wider than the top. This is the highest stone in the group. In addition, it defines the mainline of the garden motion within the composition. It’s recommended to avoid putting it ahead of other stones!
  3. Flat stone (Heart stone, Shintaiseki). In complex compositions, it’s used as a central harmonizing element, while in simpler compositions; it serves to harmonize vertical stones with horizontal lines of land or water.
  4. Branching stone (Shigyoseki). This is a stone that breaks all the rules. The top is flat and slightly wider than the base. In the most difficult case, the top is too large and looks unstable.
  5. Reclining stone (Ox stone, Kikyakuseki). The height of this stone is between the flat and branching stones. In other words, it can’t be lower than the flat one, and higher than the branching one. One edge of the stone is higher than the other. This is a fine stone placed in the front to combine other stones. In addition, it has to be placed very carefully. 

Types of Stones for Iwagumi

Choosing stones for Iwagumi is not as easy as it may seem at first glance. Even if you follow all the rules of building a stone garden, you won’t be able to achieve the desired result without beautiful and textured stones.

Unfortunately, the choice of stones for aquariums is seriously limited. After all, many types of stones, despite their beauty, will add a significant amount of substances, which significantly degrade the quality of aquarium water, making it unsuitable for aquarium inhabitants and plants.

In his works, Takashi Amano often used the following types of stones:

Manten stone

Manten stone (Iwagumi aquascape)This is one of the most popular stones belonging to the premium category. There is an opinion that these are the most ideal stones for building classic Iwagumi compositions. This stone is characterized by sharp edges, angular shapes, unique textures, and a velvety surface. All these features give this material an astonishing look of natural rocks. Most of the fragments of this stone have warm colors, but each individual stone may differ from others in hue.

Yama stone

Yama stone (Iwagumi aquascape)These stones can significantly enhance the feeling of the vast space and scale of the composition in the aquarium. Even small stones evoke an awe-inspiring sense of great age, resembling mountain boulders carved by winds and rivers.

This stone is characterized by a smoothed pattern. Its texture is quite uniform, so it’s better to arrange them randomly (scatter), rather than select the most attractive parts of the sides of individual stones.

Seiryu stone

Seiryu Stone (Iwagumi aquascape)This decorative stone is considered one of the most beautiful for aquariums. Gray and silver colors combined with sharp angles allow you making a lot of things and even creating a miniature mountain range.

Important note: Seiryu Stone contains small cavities with calcium, which may slightly increase the pH level in the aquarium. However, it’s not the biggest deal because it can be easily controlled.

Seiryu Stone – link to check the price on Amazon

Ryuoh stone

Ryuoh stone (Iwagumi aquascape)This is a truly beautiful stone with a fancy shape and an intricate surface. It’s ideal for use in Iwagumi style aquascaping.

This stone imitates the top of rocks or low-lying mountain surfaces. It’s often used in complex compositions with driftwood. It creates depth and naturalness of the scenery. To create such a layout, it’s important to pay attention to the ridgeline and the continuity of the stones.

Ohko stone (Dragon stones)

Ohko stone (Dragon stones) Iwagumi aquascapeThe stone itself is fossilized clay. It was originally mined in Japan in the coastal part of natural reservoirs. In a while, deposits were discovered in the United States, Canada, and the United Kingdom.

The main advantage of this stone is its appearance. All holes on the surface are oriented in one direction, as created by nature itself with the help of water. Visually, the Dragon Stone resembles a rock covered with dragon scales. It usually has a greenish-brown hue and is lighter in weight compared to other stones used for aquascaping.

Its surface, dotted with craters, is ideal not only as a base for planting mosses or other plants but also as a home for small aquarium inhabitants (dwarf crayfish and shrimp).

Ohko Stone – link to check the price on Amazon

In addition to the main stones, one can also find the following types in the Iwagumi style: Frodo stones, Nyasa stones (Chinese Zevra rock), Shou stone, Cliff stone, Wood stone, Yamaya stone, and Black river stone (Hakkai). 

Choosing Stones for Iwagumi

In aquascaping, the texture of stones, and the play of color and shadows is very important. for this purpose, stones with numerous cracks, potholes, as well as uneven, speckled, and complex shapes are chosen.

It’s very important that all selected stones are of the same type and color for Iwagumi. In fact, this is one of the main rules, because only the stones, which can create the impression that they were scattered into pieces many years ago after spending an eternity as a whole, can look natural. 

Key Mistakes of Beginners When Choosing Stones

  1. Beginners often try to choose only the most beautiful stones. However, when selecting the most beautiful stones, their beauty will be lost. Nothing will attract the eye of the viewer if they are all the same.
  2. Small stones are not able to show the entire image and are “suppressed” by plants.
  3. Too large stones in a small aquarium will disturb the harmony of the composition.

Perfect Iwagumi

In the case of the perfect Iwagumi style, the arrangement of stones is very harmonious and balanced.
During more than a thousand years of history of Iwagumi in Japan, certain laws were created in order to define the correct location of stones. In order to check it and to identify the pattern, scientists analyzed the most popular rock gardens in Japan, which were visited by thousands of people.

It turned out that the ideal arrangement of groups of stones forms triangles between them, and none of the sides of such a triangle intersects the group. And if you try to draw lines between groups of stones, they will resemble the crown of a tree. 

Stones in Iwagumi Rules

Why All Stones Have to be Inclined in Iwagumi?

In contrast to the classic Japanese land rock garden, where the stones are placed straight, they are tilted in the aquarium. The fact is that the concept of naturalness plays one of the main roles. In an aquatic environment, stones will always have a slight inclination under the influence of an active current. While making Iwagumi in an aquarium, we must recreate the natural environment of the underwater world.

Takashi Amano told the following about the placement of stones:
“You will never create good Iwagumi style until you learn how to place stones as fast as possible. When you spend a lot of time thinking about it, the perception is blunted, and you are already doing something unnatural while losing your sense of rhythm. Sometimes I moved the stones hundreds of times, working until the result finally satisfied me; however, the style that seemed to be finished and looked great in the evening turned out to be somewhat disappointing in the morning.

Experience and some intuition are much more important when arranging stones than artistic taste. Despite the fact that artistic taste is very important at the end of the composition, at the very beginning it’s important to understand that the stones in this place will look exactly like this and not otherwise. After you gain some experience and train your intuition in the arrangement of Iwagumi, you will reach the necessary speed of work and feel the rhythm. As a result, you will learn how to create complex, sophisticated compositions that convey the power and energy of nature.
As I mentioned earlier, it’s very important to develop the ability to see and feel things not with the eyes, but with the heart, since too many different moments are combined at once in Iwagumi: rhythm, play of shadows, balance, solemn impression, harmony, aesthetics, and refinement of the moment.” 

Plants, Fish and Shrimp for Iwagumi

Iwagumi style represents a sense of calm and simplicity. Since the stones are the center of the composition, plants are used to give more strength and power to the stones. That’s why not all plant species can be combined with Iwagumi.


Iwagumi style doesn’t tolerate chaos in plants. In the majority of cases, only one type of plant is used in the composition. The main thing is that the plants create the illusion of a vegetable “carpet“.

For example:


Talking about the fish, it’s worth noting that the following species are the most popular for Iwagumi aquariums: Cardinal tetras, Rummy nose tetras, or Harlequin rasboras.

It’s important to use calm fish while avoiding gregarious fish. This helps to maintain a more relaxed environment. It’s not recommended to use shy species, as well as those that prefer to hide in the thickets of plants. 


Amano shrimp on the rockTakashi Amano used shrimps of the Caridina multidentata species in his aquascaping compositions to fight with algae. The results of his experiments were so successful that these shrimps were used everywhere. In 2006, this type of shrimp was named Amano shrimp in order to show honor and respect to the true genius in the world of aquascaping.

The transparent color of the shrimp perfectly matches the Iwagumi concept. While removing algae from the aquarium, they never attract too much attention. That’s why other types of shrimp are usually not used in aquascaping. The thing is that their bright colors stand out from the harmony and disturb the atmosphere of the entire composition.

For more information, read my article “Amano Shrimp – Detailed Guide: Care, Diet and Breeding”.

The Sequence of Actions in Iwagumi. Step-by-Step

  1. Pour a thin layer of soil (1-2 cm) into the aquarium.
  2. Select and set the main stone at the point of the Golden section.
  3. Place secondary stones.
  4. Arrange auxiliary and decorative stones.
  5. Install driftwood (In the rarest cases! In most cases aquarists do not combine stones and driftwood in Iwagumy aquascaping).
  6. Put all the plants.
  7. Your composition is ready.
  8. Cycle the tank and add fishes or shrimp if you want to.

Equipment For Iwagumi Aquascape

It is important to understand that without good lighting, CO2 system, CO2 bubble diffuser, and filter, it will be very hard to achieve amazing effects.

Therefore, the list of necessary items (with some examples) looks like this (links to Amazon):


If the aquarium is designed in the true Iwagumi style, it gives its audience feelings of peace and pleasure and becomes a kind of small masterpiece and even a work of art. That is why experts devote years to master this technique.

Creating a true Iwagumi style that embodies the Japanese principles of simplicity and spirituality is probably only possible for professionals. At the same time, the criteria for its evaluation are rather conditional and have some kind of philosophical and even sacred meaning.

Related articles:

Aquascaping For Beginners. Introduction
How to Set Up a Dutch Aquarium
CO2 in a Shrimp Tank

Shrimp Safe Plant Fertilizers

4 thoughts on “How to Set Up an Iwagumi Aquarium

  1. Wow that was odd. I just wrote an very long comment but after I clicked submit my comment didn’t appear. Grrrr… well I’m not writing all that over again. Regardless, just wanted to say fantastic blog!

    1. Hi Calandra Martling,
      There is a very strict spam filter on my site, otherwise, I would be completely spammed.
      Best regards,

  2. What a great complete guidance for iwagumi. Just what I’ve bn looking for.
    Great thanks..
    Maybe if you make it become video with narrative.. posted on YouTube.. more people would gain benefit from it

    1. Hi Bapa Iman,
      Thank you!
      I will see what I can do.
      Best regards,

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