Order Cypriniformes
Family Cyprinidae
Subfamily Rasborinae
Genus Boraras
Found in many countries of Southeast Asia. All of these are fairly brightly colored dwarf fish, not exceeding 3 cm in length, usually even smaller. All Boraras are very beautiful and each species is interesting in its own way. This feature makes these fish wonderful objects for both species-specific and small community aquariums. The fish are also remarkably suited for nano aquariums. You can keep this fish with other peaceful fish of the same size, as well as in shrimp tanks. When combining with other species of the genus Boraras, hybridization between different species is very likely to occur, resulting in weak offspring that are sterile and often deformed.
You will not succeed if you keep Boraras with large or aggressive fish; the fish will spend all their time in plant thickets or other available shelters — after all, no one wants to be eaten. It is best to keep them in a large group in a small species aquarium with a dark substrate. The aquarium should have plenty of fine-leaved and floating plants among which they love to swim. It is good if brightly and dimly lit areas can be organized in the aquarium. Small cyprinids have developed bright warning coloration in order to compete with each other in brightly lit areas, while in case of danger they hide in the shadow.
Males of B. brigittae, B. maculatus, and B. merah are slimmer and show a more saturated red body color when excited compared to females, which are plumper. Males also display more intense black and red colors on the dorsal and anal fins. Males of B. urophthalmoides are not as colorful, but can be easily distinguished from females by a more intense coloration, especially the orange-yellow stripes above the lateral line, the iridescent blue lateral stripe, and the slim body. During the spawning period, males become more aggressive towards each other, their colors intensify, and they begin to fight for a small territory. Females lay a small number of very small eggs, and the pair shows no parental care, potentially eating their own eggs.
Boraras brigittae generally live in red-brown waters. B. urophthalmoides mostly live in clear water with high transparency. The pH of the water inhabited by Boraras ranges from 3.5 to 6.8, and hardness from 2 to 18 °dH. They prefer low hardness and low pH values, at which their coloration looks most vivid. The water should be soft, with the addition of peat extract or blackwater treatments. Keeping fish for a long time in heavily polluted water can cause gill infections.
Feed the fish with fine food that they can take in the water column. Considering their tiny size, even adult fish can and should be fed Artemia nauplii, especially since this food maintains their bright red coloration. Temperature 23–26 °C; dH up to 15 °dH.
— Boraras brigittae [Vogt, 1978]. Synonym: Rasbora brigittae. (English: Chili Rasbora, Dwarf Redfin Rasbora, Micro Rasbora Brigitte, Mosquito Rasbora). Indonesia, Borneo. 2.5–3 cm. The body is slender and narrow, the caudal peduncle is also long and narrow. The back and upper part of the head are slightly brownish. On its body, from the end of the gill cover to slightly over half of the body, there is a clearly outlined irregular green-black stripe just below the lateral line, bordered by bright red or orange stripes. The line ends with a black wedge-shaped spot at the base of the caudal fin.
In males, red or orange coloration can cover the entire body, and its brightness will only increase with age. The fins are almost transparent. The dorsal and anal fins have dark stripes along the leading edge. The outer rays of the caudal fin, the front part of the dorsal fin, and the tip of the anal fin are bright red with black spots. Broken red stripes are located on the edges of the caudal fin lobes.
Overall, males are brighter, the red coloration increases with age, they are more contrasted than females, and the green stripe is larger. The dominant male literally glows with red fire all over its body, but only after reaching 1 year of age. Subordinate males are not as picturesque. Females predominantly show shades of pink and orange and have a large belly.
The fish are outwardly similar to B. urophthalmoides, but knowing what the differences should be, you will never confuse them. B. urophthalmoides can vary in coloration (apparently depending on the habitat) and be slightly brighter or slightly paler, but it cannot be confused with B. brigittae, even with females. These are different fish. B. brigittae is much larger, while B. urophthalmoides is almost twice smaller, and an adult female grows up to maybe 19 mm. In B. brigittae, the stripe around the lateral line is red or orange, while in B. urophthalmoides it is green or golden, depending on the variety. The spot at the beginning of the caudal fin also differs in shape: in B. urophthalmoides it is round, and in B. brigittae it is wedge-shaped.
Aquarium with a dark sandy bottom, driftwood, and rich vegetation, including floating plants. They can be introduced only in a large school with other small and harmless species. If kept with large fish, the fish will spend their time in plant thickets or other shelters. Suitable for nano aquariums. Adult fish stay in the upper third of the aquarium, while the single dominant male controls about a quarter of the entire territory. With aggression unusual for a fish of this size, the male defends his domain from encroachments by other fish.
His courtship of females and “battles” with males look like this: standing head-to-head or head-to-tail with another fish, he begins to “lash” with his fins and body towards the rival, his coloration becoming more intense at this time. No physical injuries are inflicted on each other. It creates the impression that the water pressure created by body movements and color display is quite enough to keep other males under control. With a peculiar dance, the male separates the female he likes from the rest of the group and gradually leads her into a secluded corner of the aquarium.
Nevertheless, a school of these dwarf rasboras, thanks to the bright coloration of the males, will not get lost even in a relatively large aquarium, though preferably with a low water level. They draw attention with their red coloration in community aquariums. Unpretentious. Dense vegetation serves as good shelter. Several pieces of driftwood with attached Java moss should also be placed in the aquarium. In the wild, they live in slow rivers with a significant amount of humic acids and tannins, so filtration through peat is desirable.
They should be introduced into biologically mature and stable aquariums with good biological filtration. Weekly water changes are mandatory. They feed on fine live and frozen food, as well as flakes and micro-granules. Reproduction starts from 6 months. The female spawns in dense vegetation; the mating ritual takes place almost daily and mostly early in the morning. pH 5.5–6.5; dH up to 10°; T 23–27 °C.
Identification: Boraras brigittae
— Boraras maculatus [Duncker, 1904]. Synonym: Rasbora maculata, Boraras maculata. (English: Dwarf Rasbora, Pygmy Rasbora, Spotted Dwarf Rasbora, Spotted Rasbora). Fish of this species are found in ditches and ponds of the southern part of the Malay Peninsula, Thailand, Sumatra, Singapore. 2–2.5 cm. Its feature is an elongated, long body and a thin tail.
The coloration can vary from pale red to scarlet. The main body background is yellowish-red with a purple sheen. The back is brownish-red, and the main body color is reddish-pink. The pectoral part of the body is colored in silvery-yellow tones, the sides are yellowish-red, the belly is yellowish. Under fluorescent lighting, the fish appear purple. Dark spots are scattered across the body, usually not exceeding five in total.
Purple spots are arranged in a strict order: one large spot in the center of the body, others, smaller, near the anal fin and tail. At the base of the tail, a pearl spot glows brightly, which lights up especially strongly in the male during spawning. Behind the gill covers, there is a large black spot; at the base of the anal and dorsal fins, there are small dark purple spots; on the dorsal fin, there are two dark stripes. The fins are reddish. The first rays of the dorsal and anal fins are black.
Along the edges of the upper and lower caudal lobes are bright orange stripes. Pectoral fins are transparent. In some specimens, the dorsal, anal, and caudal fins are covered with contrasting black and red dashes and dots. Males have a straight belly line, are slimmer, with a predominance of red in coloration; the anal fin is red with a black border. Females are more yellowish, the belly line is somewhat more curved, the anal fin is transparent.
Peaceful, very active, staying in the middle water layer. In large aquariums, it is recommended to keep them in a school of 15 individuals separately or with small peaceful species. For a community aquarium, a selection of fish is recommended where all zones are evenly populated. It is better to keep them separately. The spotted rasbora is a water-demanding fish. The water must be crystal clear, very soft, aged, and peaty. At low pH, their coloration is most expressive. Sensitive to water changes, medications, and pollutants. The fish are thermophilic and cannot tolerate a sharp drop in temperature (not lower than 22 °C).
Dark substrate, hiding places among driftwood and leaves with sufficient swimming space, diffused light thanks to floating plants. There should be densely planted areas. Difficult to maintain. When using medications, half the dose should be applied! Juveniles acquire adult coloration at one month of age and reach sexual maturity by 4–5 months. pH 5.5–6.5; dH 2–10°; T 23–26 °C.
— Boraras naevus [Conway & Kottelat, 2011]. (English: Petch Noi, Red Micros, Strawberry Rasbora). Thailand. 1.5 cm. On the flank, there is a black spot, vertically oval in males and round in females; the stripe present in other Boraras is absent. In males, the lateral spot is significantly larger than in females. At the base of the anal and caudal fins, there are small black spots. Along the edge of the front rays of the dorsal and anal fins in males, there is black and red pigmentation; the remaining fins are transparent. Pectoral fins have a small red spot. Adult females are noticeably rounder, often slightly larger, and less intensely colored than males.
Aquarium densely planted with vegetation with swimming space. Additionally, floating plants, driftwood, or tree branches are desirable. Dominant males form temporary territories during spawning. This species is very peaceful, but not suitable for a community aquarium due to its small size and rather timid nature. Shoaling, must be kept in a group of at least 8–10 individuals.
It is not recommended to keep them with other Boraras, as hybridization may occur. Small species such as Microdevario, Sundadanio, Danionella, Eirmotus, Trigonostigma, small Corydoras and Otocinclus, as well as Caridina and Neocaridina shrimp can be added with them. Lighting should be diffused. Do not introduce this fish into a biologically immature aquarium, as they are susceptible to fluctuations in water chemistry. Filter flow should not be strong. In the aquarium, they will feed on fine live and frozen food, flakes, and granules. pH 6.0–7.0; dH 2–10°; T 24–28 °C.
Boraras merah, micros, urophthalmoides.
Genus Rasboroides, Genus Trigonopoma, Genus Sundadanio. 
