Micro costing measure (Boraras merah) Kottelat (Maurice Kottela), 1991
It belongs to the smallest aquarium fish, easy to maintain and compatible with other species of similar size. Great for small aquariums and easy to get on with shrimp.
Boraras: an anagram of the generic name Rasbor, due to the inverse ratio of the abdominal and caudal vertebrae of this kind.
Measure: from the Indonesian word merah, which means “red”, with a hint of the main body color.
Family: Carp (Cyprinidae).
Synonyms: Boraras Mera, Rasbora Phoenix.
Asia, Indonesia, Kalimantan (Borneo).
It is endemic to southern Borneo. Specimens of this type were collected in the Jelai Bila river basin at Nataik Sedavak, presumably in a settlement near the city of Sukamara in the Indonesian province of Kalimantan-Tenga (Central Kalimantan).
Location where the samples were caught “Sungei Jelai-Bila, 2 ° 41’S, 111 ° 13’E, Nataik Sedawak, about 30 kilometers south of Sukamara, Kalimantan-Tenga, Borneo.”
The range of distribution extends to the west of the Jelai-Bil watershed, while among the relative, Boraras, brigitta, with whom they can occur sympatrically (within common habitats), extends to the east.
Dwells in the “black water” duct and small rivers associated with the ancient forest peat bogs. The water is colored brown due to the release of tannins and other chemicals released by decaying organic material – fallen leaves and branches.
Such an environment is characterized by very soft (slight hardness), acidic (pH up to 4.0) water, and often very poorly lit due to the overhanging canopy. These biotopes are under serious threat in most of Southeast Asia due to human activities.
Attracts with its unusual color, the back of the fish has a light brown color, the belly is translucent, the lateral line is orange-red with a dark spot, and there are pink marks on the gill covers.
The general background is slightly reddish with a dark oblong spot on the side and a broken strip along the back half of the body. Smaller dark spots at the base of the anal and caudal fins.
The dorsal and anal fin has a dark mark along the front edge, highlighted by an intense red outline in males.
The maximum standard length is 15 – 20 mm.
This species is very peaceful, but it does not make the fish ideally suited for general aquariums because of its small size and rather timid nature. It is best to keep it alone or with other miniature species, such as Micro-collection Kubotai, Rasbor Axelrod, Danio Dracula (Danionella dracula), Barbus Eight-Striped, Wedge-Spotted Rasbory, Corridor Pygmy and small loricarises such as Otozinclus.
They are excellent neighbors for shy labyrinth / creeping, such as Chocolate Gourami, Gourami Parosfromenus or smaller species of the genus Betta, and in the aquarium densely planted with plants can be placed together with freshwater shrimps of the genera Caridina and Neocaridina.
This is a schooling species by nature and really should be kept in a group of at least 8-10 individuals. Keeping this species in a decent amount will not only make the fish less fearful, but will lead to a more spectacular, naturally-looking appearance.
Males will show their best coloring and more interesting behavior when they compete with each other for the attention of the females.
Although this fish is small, it still needs swimming space, and the dominant males form temporary territories during spawning, therefore the group is best kept in a tank with basic dimensions of at least 45 * 30 cm.
It is best to keep in a densely planted aquarium, which is an excellent choice for a carefully selected design. Adding a few floating plants, roots or branches to scatter the light entering the aquarium gives a more natural look.
Filtration should not be particularly strong, as this fish is mostly from slow-flowing waters and will have to fight the fast current.
To see it in the best possible way, make a biotope aquarium this will be an interesting solution. Soft sandy substrate is the best choice, to which you can add roots and branches, placed in such a way as to form many shaded places.
If you can not find the snags of the desired shape, then you can safely use ordinary beech or oak, if they are thoroughly dried and removed bark.
The addition of dried leaves further emphasizes the natural appearance and stimulates the growth of microbial colonies as they decompose. These tiny creatures can provide a valuable source of secondary food for the fry, while tannins secreted by decaying leaves are considered useful for fish species living in blackwater – black water.
Leaves can be left in the aquarium until completely decomposed or removed and replaced every few weeks.
Enough light should be used to imitate the conditions that the fish encountered in nature. You can add aquarium plants that can survive in such conditions, such as Thai Fern, Java Moss or Cryptocoryne.
Do not plant the Microdistrict in a biologically immature aquarium, as they are susceptible to changes in water parameters.
Temperature: 20 – 28 ° C;
pH: 4.0 – 6.5;
Stiffness: 1 – 10 ° DH.
As is the case with other species, Boraras is most likely a micro-predator, in nature feeding on small insects, worms, crustaceans and other zooplankton.
In the aquarium, take dry food of suitable size, but should not be fed exclusively by them. A daily diet of small live and frozen feeds, such as Cyclops, Daphnia and Artemia, as well as good quality flakes and pellets, will lead to increased color and will encourage the fish to go into spawning condition.
Mature females are noticeably rounded and usually slightly larger than males. Males are usually more attractive, and dominant individuals often show the most vivid and intense color.
Like many small cyprinids, this species is a fish whose eggs stick to plants and other objects or fall to the bottom, and the fish leave it unattended. That is, when mature fish are in good condition, and both males and females are present in the aquarium, a relatively small number of eggs will be deposited daily.
Therefore, in a plant aquarium, a small number of fry can appear without your participation.
However, if you want to increase the number of fry, you will need a slightly more controlled approach. An adult group of fish is prepared jointly, and one or several small, 10-15 liters, aquariums will additionally be needed.
They should be very dimly lit, either leave the bottom bare, or put some kind of mesh so that the eggs that are not stuck to the plants can fall through it so that the producers don’t get to them.
Widespread plastic grass can also be used and works very well. The water itself should be pH 5.0-6.5, 1-5 ° dH, with a temperature at the upper end of the range suggested above.
It is necessary to add a decent-sized bundle of Java moss or other small-leaf plants that fill half of the free space. Filtration is not necessary, but you can use a small sponge air filter if you want.
Then two or three pairs of well-trained producers are deposited in a spawning tank. It is advisable to transplant slowly to avoid unnecessary stress, if the conditions are suitable for them, they begin to spawn the next morning.
Although this species, of course, eats its own eggs, but they are not very actively hunting for her, as is the case with many other small carp. After spawning begins, it continues daily.
The pair (s) should be left in place for no more than a couple of days before removal, since the first larvae hatch on the second day after the initial spawning. Tiny fry live on their yolk sacs for another 24 hours or so, after which they will need an Infusorium slipper or other micro-food.
After 7 to 10 days, they should grow up enough to take Artemia nauplii / microterms, etc. As the days pass, other fry begin to appear from later spawning.
It is best to wait a week or two before starting to make small water changes to avoid unnecessary shock for the fry.
Life expectancy in an aquarium is about 5 years.
Boraras Mer has a color that is comparable to its relatives B. brigittae and B. maculatus, but can be easily identified because it does not have a pronounced color in most parts of the body, with red pigmentation concentrated around dark spots. Sometimes it is marketed with the alternative commercial name “Phoenix Pickup”.
Brigitte is the most similar, but it has a larger share of orange-red pigmentation, and dark spots on the body usually form a continuous band, whereas B. merah has a series of dots or a spot. However, there are males with a full-fledged stripe, and this has led to the assumption that B. brigittae and B. merah are the same species (Korner, 2010).
The same author reported that in the “eastern” population (the area around the city of Banjarmasin) both sexes have a strip pattern to maturity, whereas in the “central” population (the city of Palangkarai, where fish is caught for aquarium trade), only in males strip and only at puberty. Kottelat (2013) argued that different ontogeny * in color and the expected geographical distribution of these two populations support the existence of two species.
The Boraras species were established in 1993 to separate a small group of species from the larger Rasbor community based on differences in morphology and reproductive behavior.
The genus Rasbory is divided into six species (groups of closely related species), of which Boraras (B. brigittae, the only species participating in the study) are included in the third group together with Horadandia atukorali, Rasboroides vaterifloris, Trigonostigma heteromorpha and three species that were previously included in Rasbor , but were transferred to new genera; Trigonopoma gracile, T. pauciperforatum and Rasbosoma spilocerca.
From this it was established that they form a monophyletic group with the Rasboroids, which means that they come from the same common ancestor. The results for B. brigittae and T. heteromorpha were found to be inconclusive, and further work was recommended regarding their phylogenetic position.
The small size of the adult species of Boraras has evolved through a process known as miniaturization, characteristic of mature adult fish with a significantly smaller size of less than 20 mm.
Carps are one of the few groups in which this phenomenon occurs regularly with all species of Barboides, Danionella, Microdevario, Microrasbora, Horadandia, Boraras, Paedocypris, Sawbwa and Sundadanio, which are miniature taxa *, as well as several representatives of Danio, Laubuk and Rasbor. All of them prefer stagnant or slow-flowing water bodies, often in nutrient-poor habitats, such as forest peat bogs.
The species of Boraras from the Malay Archipelago (B. brigittae, B. maculatus and B. merah) have a thinner and more elongated body profile than are from Indochina (B. micros, B. urophthalmoides, B. naevus), this can help when trying identify them.
* Ontogenesis – a set of processes of individual development.
* Taxon – a group in the classification, consisting of discrete objects, combined on the basis of common properties and characteristics.