Seiryu Stone: What is an Aquarium Seiryu Stone Rock?


A Seiryu Stone is a blueish grey colored stone that originates in Japan. They can be identified by the jagged ridges and the white calcite veins that run through it. Since these stone have characteristics that uniquely represents stones in nature, they have gained popularity as a hardscape material for aquariums.

Seiryu Stone, also known as Seiryu-Seki (青龍石), gets its name from the “Azure Dragon,” which is a mythical constellation of a dragon with beautiful blue scales. The Stone is named for the blue scales of the dragon.

Ever since it was introduced to the aquarium hobby, its popularity have soared as an aquascaping material. Due to its increased popularity, Seiryu Stone are now sold in many places outside of Japan. However, the high demand have resulted in regulations as well. It is now illegal to export Seiryu Stone from Japan. While there are many stones on the market labeled as “Seiryu Stones” worldwide, some are not true Seiryu Stones.

True Seiryu Stones are very dense, and because of this, you should be careful when stacking them in your aquarium. The higher density is because Seiryu Stone is a limestone based stone. If you end up with one of these gorgeous stones, it is important for you to wash the stone thoroughly underwater first. This is to get rid of debris and other impurities that may contaminate your aquarium water. You will want to boil your Seiryu Stone in water for thirty minutes. This will help kill off any harmful bacteria, or micro organisms that may be on the stone.

Seiryu Stone

Seiryu Stone Facts:

  1. Due to their popularity and high demand, Seiryu Stone is now illegal to export from Japan.
  2. Seiryu Stone looks very similar to Ryouh Stone, and many times they are mistaken for one another.
  3. The Seiryu Stone became popular in aquascaping when it was introduced to the hobby by Takashi Amano, who created the Amano and Iwagumi styles of aquascaping.
  4. Seiryu Stones can raise the pH of the aquarium due to the amount of calcium carbonate in the rock.
  5. Seiryu Stone is a limestone based stone, and this causes it to have a higher density.

Why Use Seiryu Stone In Your Aquascape

Compared to the stone you can find in your backyard, Seiryu Stone is definitely not the cheapest option. It’s not the easiest to obtain either. As mentioned earlier, Seiryu Stone can’t even be exported from Japan. Why should you go through the trouble of using using Seiryu Stone for your aquascape?

Seiryu Stone is not often used in aquascaping to create caves, mountains, and ledges in your aquascape. These stones are full of character, which lets the aquarium come to life. They are often selected for its stunning color, and will help provide the perfect background decor to help your fish and plants stand out. If you have fish that enjoy a higher pH, this rock is a great choice as it will help keep the water pH at the desired level.

Seiryu Stone has a porous texture that works amazingly well to help facilitate the growth of microorganisms in your tank. It can provide the right environment for them to grow on. This can be beneficial for the fish as well, since it helps create a balanced ecosystem.

Using Seiryu Stone in your tank is also beneficial to help give your fish places to hide, and can be used to mimic the fish’s natural environment. This can help reduce the stress of your fish, and help them become more comfortable in their habitat. A well positioned stone may even encourage fish to lay their eggs on them.

Seiryu Stone is a great choice for longevity as well. It is extremely durable and does not break apart as easily, or wear away like other rocks do.

When purchasing Seiryu Stone for your aquarium, a good amount to purchase would be roughly 1 to 2 pounds of rock per gallon of water in your tank. While this may sound like a lot of rock, keep in mind that these stone are dense heavy rocks.

Breaking Seiryu Stone

Seiryu Stone can be difficult to break apart. If you simply take a hammer to the stone, you will get small shards, and they may not be the right size or the right shape you wanted. Seiryu Stones tends to break into small shards because of the calcite veins that run through it. If you find yourself with Seiryu Stones that you want to break down, it would be better to use a hammer and a chisel. This will help you achieve the desired shape and size.

Does Seiryu Stone raise pH

Many stones contain acids, carbonates, and many other minerals that will cause shifts in the water chemistry of your aquarium depending on how many pounds of rock per gallon you add to your tank. Since large changes to the water parameters could affect aquarium fish and plants, you will want to make sure you know what stones you are putting into your tank and what they can do. It is important to know that igneous rocks like granite will not change your water chemistry, but sedimentary and metamorphic rocks like limestone and marble, will affect your water chemistry.

Seiryu Stone is a metamorphic rock, and it will affect your water chemistry. It has a strong effect of the pH of the water in your aquarium because it contains calcium carbonate. The calcium affects the GH, and the carbonate affects the KH of the water. You will notice and increase in the pH and the water hardness when using this rock in your aquarium setup. This can be seen as a bonus if you are keeping fish that enjoy these water parameters, such as Lake Cichlids.

Seiryu Stone may raise the pH level in your aquarium, but the effects should be fairly insignificant. However, keep in mind that the more Seiryu Stone you put into your aquarium, the more it will rise. In addition, if you have a small aquarium, one large stone may have an impact on the pH levels. It is always important to monitor your water parameters when adding anything into your tank, as slight water changes can affect sensitive plants and fish. Adding in driftwood to your aquarium may help offset the raised pH of the water caused by Seiryu Stones in your aquarium.

Where to Find Seiryu Stone

Seiryu Stone can be found in Japan, however it is now illegal to export them. There are similar stone that are widely available, but it does not contain the same minerals as true Seiryu Stone. If you do manage to find true Seiryu Stone, expect them to be quite pricey.

Sourcing Seiryu Stone from local pet stores may be challenging. However, you may be able to find them from a reputable retailer online. When purchasing Seiryu Stone online, you usually do not get to pick out individual pieces. You will most likely have to work with what you end up with, and this can be frustrating to aquascaper. Therefore, if you are purchasing these stone online, try to purchase a little more than you think you need. This will allow a little margin for the pieces you simply can’t use.

Be Aware of Fake Seiryu Stone

Unfortunately, due to their popularity and demand, it is illegal now to export Seiryu Stone from Japan. This is causing a scarcity in supply, which is also incentivizing sellers of fake Seiryu Stones. Many of the stones being sold online as Seiryu Stones are actually Ryouh Stone.

Ryouh Stones similar in color to Seiryu Stone, but it lacks the blue hue that true Seiryu Stone actually has. Ryouh Stone will have a duller appearance in comparison. Ryouh Stone has white veins that run through it just like real Seiryu Stone. However, if you look closely, you will see that the Ryouh stone is more dull grey in color. Keep in mind that it can be difficult to find true Seiryu Stones. If you wish to purchase true Seiryu Stones, it is important to know the properties and distinctive markings. There are many sellers that advertise their rocks as Seiryu Stone, when it is actually not. Many of these sellers may not even be aware that they are not selling the true stone. This is why buying from a reputable seller is also important, especially since you have to trust the photos when purchasing them online.

Seiryu Stone VS. Dragon Stone

Seiryu Stone and Dragon Stone are very different stones in the aquascaping hobby. Seiryu Stones will raise the pH of your water parameters, and the Dragon Stone will not. Dragon stone is a brownish, reddish, earth toned, colored rock that has a pitted look to it. This stone is also popular in aquascaping for its interesting look. Dragon Stone is available to purchase online, and it is highly recommended by many aquascapers. Seiryu Stones are very difficult to break down into smaller pieces, but Dragon Stones are very easy to crush.

With all the different types of rocks out there for aquascaping, Seiryu Stone is a great choice to use if you can acquire it.

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