Cooperation: OFY Sagami, Hiroyuki Kiko (TEAM BORNEO)

first

This time we will introduce an extremely small species of the genus Sundadanio, known by the name Rasbora axelorodi "Neon Blue". Let's feature the Sunda Danio, which is a small carp family and has a shine that rivals neon tetras and cardinal tetras.

What is Sunda Danio?

Sundadanio is distributed in Indonesia.SundadanioIt is a member of the genus carp, which is extremely small and has a total length of about 2 cm. Formerly Rasbora (Rasbora) is a fish of the genus Rasbora axelorodi (Rasbora axelrodi) was known. However, in 1999, a new genus was established by Dr. Maurice Kottelat, a Swiss ichthyologist who is famous for Asian fish classification, and it was reclassified to the genus Sundadanio. Although this was not a big topic in the Japanese aquarium world at the time, it did become a hot topic among enthusiasts of small carp fish. I was surprised that the big name ``Sunda'' was given to Rasbora axelrodii, which was a fairly minor entity even at the time, and I felt that the person who named it had a lot of love for this fish. The core enthusiasts thought, ``Good job on naming it.''SundadanioSunda means Sunda Islands in Asia, and comes from the fact that this fish is distributed in the Greater Sunda Islands (a name that includes Sumatra, Java, Borneo, Sulawesi, and surrounding islands). Danio is a general term for small carp in the language of Bengal, India, and means ``small carp of the Greater Sunda Islands''. Isn't it a pretty grand name for a small fish?

By the way, the species name Axelrod was dedicated to the late American tropical fish expert Herbert Richard Axelrod. He founded TFH, a pet publishing company, in 1952, and in the pre-internet era, TFH's magazines and books became the bible for aquarium fish enthusiasts around the world. Cardinal Tetra (Paracheirodon axelrodi) and black neon tetra (Hyphessobrycon herbertaxelrodi), his work has had a great influence on the world of ornamental fish around the world, as his name has been dedicated to various ornamental fish. I used to be a big fan of TFH's books, and those who can associate the name Axel Rody with TFH are probably seasoned enthusiasts. Maybe (lol)

In 2011, there are 8 types!

Now, in 1999, it was Rasbora Axellodi, or Sundadanio Axellodi (Sundadanio axelrodi), but in the aquarium world it was known that there were several individuals with different colors. Even the same Axel Rodi was divided into blue, green, and deep blue based on the depth of the color, and clearly red individuals were considered red, so they were distinguished among enthusiasts.

In 2011, the genus Sundadanio was reclassified to include individuals with different body colors, and the genus Sundadanio now consists of eight species, including the new species. This reclassification was also carried out by Dr. Kottelat and his colleagues (Kevin W. Conway, Maurice Kottelat, Tan Heok Hui, 8). This announcement had quite an impact on small fish enthusiasts, but it also raised the hurdle for identification. This is because there are quite a few species that resemble Axelrodii. For example, Gargula (S. gargula) and margarition (S. margarition), Atoms (S. atomus) Goblinus (S. goblinus) etc. are very similar to Axel Rodi. This means that 8 of the 5 species are very similar. Hmm, I'm in trouble. What is important here is the distribution area. This is because the eight species of the genus Sundadanio currently have distinct distribution areas.

Is it Axel Rodi?

The question then becomes whether the individuals circulating under the name Axel Rodi are really Axel Rodi. The bottom line is, ``Hmm, I don't know.'' Currently, the ones that are commonly distributed are those imported from Indonesia under names such as Rasbora axelorodi "Neon Blue" and "Blue," and these are thought to have been collected locally. Since they are imported in constant numbers throughout the year, it can be inferred that their habitat is a rich environment that can support a large number of individuals over a fairly wide area. At present, we do not know the details of where it was collected, so we cannot be certain that it is Axelordi.

Here, I have created a table showing the distribution areas of the eight species of the genus Sundadanio based on the 2011 paper, so please refer to it. The distribution of Axelrodii is Bintan Island. On the other hand, Gargula, which is very similar, is located on Bangka Island, Atoms is located on Singkep Island, Goblinus is located in Jambi, Sumatra, and Margarithion is located in Sarawak, Malaysia. Currently, there is no commercial export of locally collected fish from Sarawak, Malaysia, so it is unlikely that margarition will be distributed as an ornamental fish.

Of the four species including Axelrodii, the one that seems to have a wide distribution range is Goblinus, which is distributed in Jambi Province, Sumatra. Next is Gargula on Bangka Island, Axellodi on Bintan Island, and Atmus on Singkep Island. I can't say whether a large number can be continuously supplied from the same area because I haven't actually seen the habitat, but I think it would be possible from a wide area such as Jambi province. Also, fish from the same region are not always distributed, and sometimes fish collected from various regions may be collected and exported. Considering this, at present the Axelroddy reference species (Sundadanio cf. axelrodi) is it appropriate? Currently, it is not Rasbora, so if the common name is Sunda Danio "Neon Blue", it may be easier to understand and avoid misunderstandings. Here, I will explain it using the abbreviation Neon Blue.

Existence of Axel Rodi “Red”

There is also a Sunda Danio known as Axelrodi "Red" for some time. This is also a remnant of the time when only Axelrhodi was described as a species, so it was given the name Axelrhodi, but enthusiasts thought it was clearly a different species. It's obvious that it's not Axel Rodi, so it would be smarter to call it something like Sunda Danio "red". Here, it will be explained as red.

The characteristic red color is the redness of the body and the thin red line running down the side of the body, and in mature individuals, a metallic green color can be seen on the upper part of the body side. Due to these characteristics, a new species of Rubellas was described in 2011 (S. rubellus), echinus (S. echinus), Retiarius (S. retiarius) is considered to be identified as one of the following. Judging by the red lines on the side of the body and the green coloring that are commonly seen in reds, it seems that the closest one is rubellas. Similar to the Axelrodii reference species, currently the Rubellas reference species (Sundadanio cf. rubellus) would be appropriate. However, depending on the imported individuals, some have less conspicuous green coloring and others have short red lines on the sides of their bodies, and like Axelrodii, it is difficult to identify the species unless the collection site is known. It is also possible that the species is different from the three species mentioned above. Here I am posting the red one I got in 3 and the one I got in 2012, but if you compare them, you won't know if they are the same species.

Ecology

The Sundadanio family is quite timid in nature. If you stand in front of an aquarium or startle them, you will see them running away in groups, but they probably live in groups as well, running away from predators in the same way. However, this is not to say that they are simply timid; once they get used to the environment in the aquarium, they can be seen spreading their fins and chasing away individuals that approach them while securing their own position, albeit within a small area. Masu. This behavior can be seen everywhere when the number of breeding animals is large, but when the number of breeding animals is small, strong individuals can be seen to drive away other individuals quite violently. However, although they will chase away other individuals, they are unlikely to harm them. This behavior is more noticeable in males. It can be said that the ecology of the Sundadanio is that it behaves in groups while intimidating other individuals, and even though it is small, I never get tired of watching the playful behavior it sometimes shows. When breeding, please try keeping 5 or more to enjoy group behavior.

Male and female difference

The neon blue male has a large and clearly colored red-black fin, and is characterized by a reddish abdomen. On the other hand, females have slightly smaller anal fins, and although they do have some coloration, it is subtle, and some individuals have almost no coloration at all. In young individuals, the development and coloring of the anal fins are insufficient, and the gender difference is not clear.

Habitat condition

The Sunda Danio's habitat is peat swamps called peat swamps and small rivers flowing through forests, and it seems that they often live in black water or brown water. This time, we were able to borrow photos of the Sunda Danio habitat on Bangka Island and ask Hiroyuki Kiko of TEAM BORNEO, a fish hunter whose main activity is in Indonesia, about the local situation. So I will introduce it here.

Bangka Island is the distribution area of ​​Gargula. In its habitat in the northern part of Bangka Island, Licorice gourami Jurinae species (Parosphromenus juelinae) is also said to live there, and the water quality data of the river where it lives indicates that the pH is 4.8. The pH value is quite low, but this is normal for Indonesian peat swamps. The hardness of the water is GH0-1, KH0-1, and the electrical conductivity is 0 microSiemens, values ​​that cannot be measured, so it can be said that the water is quite clean. Taking this water quality into consideration is the key to keeping Sunda Danio for a long time. The rivers it inhabits are small rivers with gentle flow, and depending on the location, Cryptocoryne longicauda (Cryptocoryne longicauda) and other aquatic plants of the Araceae family are said to grow densely. Cryptocoryne is an aquatic plant that only grows in areas where the water is clean and disappears as soon as the water becomes polluted due to development work. The Sunda Danio lives in places with such clean water.

Distribution and acquisition

Currently available are neon blue and red, but the former has a higher distribution volume and is easier to obtain throughout the year. All of them are wild specimens collected locally, and I feel that there are many red specimens that are a little thin, but I think that neon blue specimens are in good condition. For those who know the import status of Sunda Danio over 30 years ago, it feels like a world away. In the past, there was a time when the amount of distribution itself was small, but many specimens were imported in poor condition, such as being underweight or infected with diseases, and even if they were finally obtained, they often became stars before they could be recovered. There was also. Compared to those days, management from collection to import seems to have improved considerably, and I'm especially happy that Neon Blue is now available in good condition and not too thin. However, it is still a delicate fish, and if it is handled roughly at a shop, it will often go out of shape, so it is important to observe the fish carefully before purchasing. If an individual is swimming briskly with its fins taut, has a good color on its body surface, or is chasing away other individuals, it should be in good condition. Just like the chocolate gourami introduced last time, it is important to obtain one in good condition, so be sure to choose one carefully.

By the way, it is currently difficult to obtain species other than neon blue and red. In the early 2000s, there was an individual that was distributed under the name "Lasbora Axelrodii Black". It used to have a color pattern similar to that of Axel Rhodi, with a red line running down the center of its body, but it is no longer visible. If such individuals were to be imported, the Sunda Danio would become an even more attractive group. Am I the only one who thinks that if it becomes possible to obtain specimens with a clear locality such as where they were collected, it would become a more enjoyable hobby? This is my personal opinion, but there are still many unknown Sunda Danios in the vast Sunda Archipelago. I look forward to the emergence of new species in the future.

Key points of breeding

There are some negative words to keep in mind when breeding them, such as ``timid'' and ``delicate,'' but if you can get an individual in good condition, breeding them will not be as difficult as you might think. Let's bring out the bright neon blue glow by keeping in mind the key points of breeding.

◆Example of breeding neon blue
This time I am using a 30cm cube aquarium to swim 15 neon blues. We used plenty of Microsolm ``Wavey Leaf'' to reduce stress by creating a layout that allows you to escape to the space behind you if you are surprised. Soil is used for the substrate and the pH value is adjusted to around 5. The bottom of the water is lined with fallen leaves, imagining an underwater stream in Southeast Asia. This is collected from mountain streams in Japan and is used after being boiled and sterilized. In fact, the neon blue swimming here is an individual that cohabited with Chocolate Gourami and Boraras brigittae in the fourth part of this column. As long as the fish do not attack neon blue, you can enjoy swimming with them without any problems.

■Aquarium data
Aquarium: 30cm wide cube tank
Filter: External filter
Filter material: wool mat + soil type
Substrate: Soil type
illumination:light up 300 white(Using a timer to set the brightness to 70% and turn on for about 1 hours a day)
timer:LED smart timer
Aeration:Suishin SSPP-3SAerate all day using
Water temperature: 26℃
Food: Granule type or flake food in the morning, brine shrimp larvae and frozen daphnia at night, sometimes
Breeding organisms: Sundadanio “Neon Blue” (15 animals), a type of Lepidocephalictis (1 animal)
Aquatic plants: Microsolum “Wavey Leaf”

●Aquarium
Neon Blue is an extremely small species with a total length of about 2 cm.They live in groups even though they have loose territories.Because it has an ecology ofIt is recommended to keep them in groups of 5 or more.Also, this species has a delicate snout, so if you keep it in a small aquarium, it may rub its snout against the glass surface when it gets startled and runs away, causing the epidermis to peel off. The snout can also be damaged if the fish is temporarily placed in a small container such as a plastic case when purchasing or transporting the fish. It will heal naturally after a while, but be careful as there is a possibility of bacterial infection. For this reason, it is desirable to keep even very small species in as large an aquarium as possible. In this breeding example, we are using a 30cm cube aquarium, but I feel that 30cm in width is the minimum width.If you want to keep 10 or more fish, use an aquarium with a width of 45 cm or more.This will reduce the chance of injury to the mouth and stress on the fish.

●Water quality
As I wrote earlierThey live in clean, soft water with a pH of less than 5.doing. In actual breeding, if the water is clean and they are well adapted to the environment, they will do well even if the water is neutral. However,If you are aiming for long-term breeding, maintain soft water with a pH of around 5 to 6.5.It would be better to do so. Therefore, avoid using stones or aquarium accessories that make the water alkaline. Once they have adapted to the environment in the aquarium, you will find that they are surprisingly hardy fish.

●Filter (filtration)
You can use any type of filter that fits the size of your aquarium. If there is a gentle current, you can see them swimming briskly towards the current. The internal expression “Suisaku Space Power Fit Plus"series,"Suishin seriesA bottom-mounted type operated by an air pump such as ``Suisaku bottom filter” series, which can be attached to the glass surface of an aquarium.Suisaku panel filter” is recommended because it makes it easy to create a gentle water flow.

●Filter material
Do not use anything that makes the water alkaline.. Use something that does not affect water quality or makes it slightly acidic.

●Bottom sand
Soil-based bottom sand is the easiest to create soft water quality, but gravel-based bottom sand can also be used as long as it does not affect the water quality.

●Water temperature
Maintain 25-26℃To do. It is not good for the high temperatures to continue, so in the summer, do not use air conditioners orMini cool fan USBstyleUse an aquarium cooling fan such as `` to lower the water temperature.

●Lighting
Lighting is also necessary for observing neon blue colors and growing aquatic plants. The neon blue body surface glows green or blue depending on the angle of light. If you turn off the aquarium light and observe it with indoor lighting, you can enjoy a different body color. In this breeding example, there is a timer that can adjust the brightness of the light.LED smart timer'' for 1 hours a day, and the brightness is set to 6% to create a slightly dim environment. This is due to my personal belief that neon blue cats tend to calm down in a dimly lit environment, but I have actually been able to raise them well. In addition, strong light makes it easier for moss to grow, so the purpose is to prevent that from happening.

●Bait
Neon blue isThey will eat artificial feed and raw food, but they are very picky, and when it comes to artificial feed, they prefer small-grained, soft foods such as fine flakes and medaka food.They will also eat things that are floating on the surface, but they are not very aggressive and seem to be more likely to eat things that sink slowly. Even if they eat hard food, they will often spit it out and not eat it. Frozen feed will eat small items such as brine shrimp larvae and daphnia.I especially like hatched brine shrimp larvae.And this one will actively eat it. By the way, compared to Neon Blue, Red is a surprisingly big eater and can be observed actively eating artificial food floating on the water surface.

One thing to keep in mind when feeding your fish is that in the early stages of introducing an aquarium, you may not know what food they like, and there will be a lot of uneaten food, which can lead to diseases due to poor water quality, so it is important to find food that they often eat as soon as possible. Therefore, it is a good idea to mainly feed brine shrimp larvae to improve the condition of the individual in the early stages of introduction into the aquarium, and once the condition improves, it is a good idea to give them artificial food as well to find their favorite food. AlsoThey do not eat food that falls to the bottom of the water, so they have creatures living with them that can immediately process the remaining food.. Recommended foods include small, gentle tropical loaches such as coolie roach, and shrimp. However, leftover food alone may not be enough to feed them, so be sure to keep a close eye on these creatures and feed them an appropriate amount of food, such as sinking feed. In addition, in this breeding example, a type of Lepidocephalictis (a type of small tropical loach) was used as a cleaner.Lepidocephalichthyssp.) living together. We are able to live together without any problems because we are not interested in each other.

●Layout inside the aquarium
It goes well with aquatic plants, so place them appropriately and secure a swimming space.Let's do it. I think it would be better to have a place where he can hide because he is timid. Neon blue can be unsettling in open layouts with no hiding places. It's also fun to see neon blue against a dark background such as the shade of aquatic plants. Also, if you are conscious of the location, it would be interesting to place plenty of cryptocorynes and recreate the scene of neon blue swimming around them. However, you will also need techniques to properly cultivate cryptocoryne.

- Mixed swimming with other fish
Any fish that does not attack Sundadanio can be mixed with it without any problem.. Last time when I was swimming with Chocolate Gourami, I had Boraras brigittae, which is smaller than Neon Blue, with me, but Neon Blue sometimes seemed to chase Boraras away. However, it does not attack and cause damage, so it is okay to mix it with fish smaller than Sundadanio.

Fish suitable for mixed swimming
・Medaka friends:Small species such as lampeye and origias
・Small characin: Small species such as neon tetras
・Small carp: Small species such as Espei and Boraras
・Small cichlid: Small aquariums can be stressful for Sunda danios, so check the situation in a larger aquarium.
・Anabantid: Possible for small species such as licorice gourami and pygmy gourami.
・Gentle catfish: Small species such as Otocinculus and Corydoras
・Loach: Gentle species such as coolie roach
・Small crustaceans such as shrimp：Small species such as Yamato Numa shrimp and Minami Numa shrimp

●Daily management
Since it is an extremely small species, it does not pollute the water very often if this species is the main breed, but even so, if you neglect to change the water for a long time, it may suddenly go out of shape. ThereforeIt is a good idea to clean the substrate and change the water while removing moss from the glass surface.Probably. In that casemaintenance goodsYou can comfortably clean and change water using the . There is no problem if you use water for water changes that has been adjusted with a pH lowering agent.

●About illness
Diseases are most likely to occur immediately after purchase or when infected fish are introduced.This is a case of infection. As I mentioned earlier, in recent years many imported fish in good condition have been distributed, so there are fewer problems after purchase, but even if the fish just imported seem to be in good condition, they may be infected with bacteria. There may be cases. If your fish swims with its fins closed after you introduce it into your aquarium, or if you notice pepper-like white dots appearing on its body surface or fins, it is likely that it has a bacterial or parasitic infection, so give it a medicated bath using a fish medicine. Another option is to give your fish a medicated bath in another tank to quarantine it, without introducing it to the main tank immediately after purchase, even if there are no symptoms. At this time, do not put sand or aquatic plants in the aquarium and manage it while feeding it. Let's keep an eye on it for about a week and if it doesn't show any signs of illness, it's safe to move it to the main tank. If you use this method to quarantine newly purchased fish when introducing them into an aquarium where you are raising Sunda danio, the probability of introducing diseases will be lowered and you will be able to prevent problems from occurring.

●Possibility of breeding
I've never heard of neon blue breeding, so I think it's quite a hurdle. At my place, I saw what appeared to be a male and a female playing together behind aquatic plants, so I was excited and wondered if they were laying eggs, but I haven't seen any such behavior since then. not. If you keep only this species in an aquarium with plenty of aquatic plants in a good environment, you may find that they are breeding before you know it. First of all, it is important to keep the fish in good condition and raise them properly.

● Conclusion
The neon blue fish, which has a metallic blue-green body and red-black tails, is a beautiful fish that you will never forget once you see it. Its beauty is top class among the small species of the Cyprinidae family. Although it is not yet well-known enough to be called a popular species, it is a recommended fish for aquarists who want to take a step up. Please enjoy the charm of this fish by raising it carefully and bringing out its beauty. see you!