Neon Blue Rasbora – Boraras spp.

Among the tiniest aquarium fish available, the neon blue rasboras of the Boraras group are absolute gems. Their shimmering bodies, delicate silhouettes and peaceful nature make them ideal for nano aquariums and heavily planted tanks. They are also a perfect introduction to the fascinating world of microfish, where even a small aquarium can become a thriving, colorful underwater landscape.

Who Are the Neon Blue Rasboras – Boraras spp.?

The name “neon blue rasbora” is used by aquarists for several small species within the genus Boraras. These fish are close relatives of the better-known rasboras from the genus Trigonostigma, but are much smaller and more delicate. Under the common name “neon blue rasbora” you can encounter, for example, forms and local variants of:

• Boraras brigittae – often known as chili rasbora, typically red, but some lines show a distinct bluish iridescence
• Boraras merah – small, intense red fish with subtle blue reflections
• Boraras urophthalmoides – sometimes sold as neon rasbora or micro rasbora
• Boraras naevus and Boraras maculatus – other tiny, spotted species with varying metallic sheens

In trade, the exact species is not always clearly determined, and different suppliers may use the same common name for slightly different fish. However, all Boraras species share several features that are important for aquarium care:

• Length usually 1.5–2 cm, rarely more than 2.5 cm
• Very peaceful, schooling fish
• Preference for soft, acidic and clean water
• Need for dense vegetation and hiding places
• Sensitivity to sudden changes in water parameters

From the aquarist’s perspective, the exact species is often less important than understanding these general requirements. When choosing neon blue rasboras, it is more crucial to ensure that you obtain healthy, active fish from a reliable source and that you are prepared to provide them with the right environment.

Natural Habitat and Behavior

In nature, Boraras species inhabit slow-flowing forest streams, peat swamps and flooded areas of Southeast Asia, especially in Indonesia, Malaysia and Thailand. These waters are often stained a tea-like brown by tannins from leaves and wood, with very low mineral content and a slightly acidic to clearly acidic pH.

Typical features of their natural environment:

• Soft, dark substrate composed of sand, mud and leaf litter
• Submerged roots, branches and fallen leaves that create a network of hiding places
• Weak current and calm water surfaces
• Filtered light, often dimmed by dense vegetation above the water
• Abundance of tiny invertebrates serving as natural food

Neon blue rasboras form tight shoals and spend most of their time in the middle and upper water layers, occasionally exploring near the bottom between plants and roots. In a secure, well-structured aquarium they show very interesting behavior:

• Group swimming and synchronized turns
• Subtle hierarchical displays, but without aggression
• Curious hovering near floating plants and roots
• Short, lightning-fast dashes to catch drifting food

Understanding this natural lifestyle helps to design an aquarium in which Boraras will feel safe and display full coloration. The more closely we mimic their habitat, the more intense the neon blue sheen and ruby hues become.

Aquarium Setup for Boraras: Size, Layout and Equipment

One of the advantages of neon blue rasboras is that they are ideal for small aquariums. However, “small” does not mean “overcrowded jar.” They still need stable conditions and enough space to swim as a group.

Aquarium size

For a basic shoal of 10–12 Boraras, an aquarium of 20–30 liters is the minimum. For richer aquascapes, more complex communities or larger groups (20–30 fish), 40–60 liters is much more comfortable. A larger water volume makes it easier to keep stable parameters and is often actually simpler to maintain, especially for less experienced aquarists.

MB Store offers a wide range of aquariums suitable for nano fish, including minimalist glass tanks ideal for planted layouts, as well as complete sets with dedicated covers and lighting. Carefully chosen equipment allows you to create conditions very close to the natural habitat of Boraras while maintaining an elegant look in your home or office.

Filtration and water movement

Although Boraras come from calm waters, they still need proper filtration. However, the flow must not be too strong, or the fish will constantly struggle against the current and become stressed.

• Small internal filters with adjustable output
• Sponge filters driven by an air pump (excellent for breeding tanks)
• Mini external filters with a spray bar directed toward the glass

In all cases, the key is gentle movement and maximum biological filtration, not high mechanical power. MB Store offers filters and sponges tailored to nano aquariums, helping you choose a solution that combines efficient filtration with delicate flow.

Lighting

Neon blue rasboras look their best under moderate lighting. Very intense light without shade can stress them and reduce their willingness to swim in open areas. The ideal setup:

• LED lighting with adjustable intensity
• Areas shaded by tall plants and floating vegetation
• Daily cycle of 7–9 hours of light to avoid excessive algae growth

High-quality LED lamps from MB Store enable fine-tuning of brightness and color temperature, allowing both plants and fish to present themselves in full glory.

Substrate and decoration

To help fish feel safe and encourage natural behavior, it is worth designing the aquarium as a small “blackwater” or forest stream:

• Dark sand or fine gravel that accentuates colors
• Roots and branches (e.g. mangrove, spider wood) forming a network of shelters
• Catappa leaves or oak and beech leaves, prepared appropriately
• Small stones and pebbles to diversify the bottom

Leaf litter and driftwood will gradually release tannins, slightly darkening the water, lowering pH and creating a more natural look. This kind of biotope also adds a sense of depth and tranquility to the aquarium, which benefits both fish and observers.

Water Parameters and Maintenance

Neon blue rasboras come from soft, often acidic waters. Although tank-bred fish are usually more adaptable than wild-caught, providing conditions close to their natural habitat significantly improves their health, color and lifespan.

Recommended water parameters

• Temperature: 22–27 °C, optimally around 24–25 °C
• pH: 5.5–7.0, with a gentle preference for slightly acidic values
• GH (general hardness): 1–8 dGH
• KH (carbonate hardness): 0–4 dKH
• Ammonia and nitrite: always 0 mg/l
• Nitrate: preferably below 20 mg/l

Because Boraras are very small, they react quickly to toxins in the water. Careful filtration and regular maintenance are crucial.

Water changes

For a well-stocked nano aquarium, weekly water changes of about 20–30% are recommended. In very small tanks (20–25 liters), smaller but more frequent changes, such as 10–15% twice a week, can help to maintain stability.

• Always match temperature of new water to tank water
• If tap water is hard or alkaline, use reverse osmosis water mixed with tap water or use appropriate conditioners
• Add new water slowly to avoid sudden parameter changes

MB Store provides conditioners, test kits and RO systems that allow you to fine-tune water parameters for demanding microfish like Boraras.

Blackwater and tannins

Many aquarists choose to add tannins to the water using catappa leaves, alder cones or special liquid extracts. This darkens the water slightly, which:

• Has a mild antibacterial and antifungal effect
• Reduces stress and enhances natural behavior
• Accentuates neon and red colors of fish

It is worth doing this gradually and monitoring fish reactions as well as water chemistry. Blackwater-style aquariums are especially attractive visually when combined with elegant tanks and equipment, as available from MB Store, which emphasize the natural beauty of this type of setup.

Feeding Neon Blue Rasboras

Due to their tiny mouths, Boraras require suitable food particle sizes. They are micropredators that in nature feed mainly on tiny organisms in the water column.

Basic diet in the aquarium

• High-quality micro flake foods that can be crushed further
• Micro pellets specifically formulated for nano fish
• Fine granules that sink slowly

Before feeding, flakes can be rubbed between fingers to reduce their size, ensuring that all fish can easily ingest them. Food should be offered in small portions so that everything is eaten within a few minutes.

Frozen and live foods

To fully bring out the neon blue and red coloration, it is worth regularly supplementing with protein-rich foods:

• Frozen cyclops
• Frozen daphnia
• Very small Artemia nauplii
• Microworms and vinegar eels for fry and small juveniles

These foods very effectively stimulate natural hunting behavior. Just ensure that the particle size is small enough for Boraras to ingest comfortably.

Feeding frequency

• Adult fish: 2 small meals per day
• Fry and young fish: 3–4 small meals daily

Because neon blue rasboras are minute, their stomachs are also very small. Overfeeding is one of the most common mistakes leading to poor water quality. Uneaten food quickly decomposes; therefore, careful dosing of food is a sign of responsible care.

Tankmates and Community Setups

Neon blue rasboras are exemplary community fish, but because of their size and sensitivity, not every tankmate is suitable. When planning a community aquarium, the golden rule is: no potential predators, even if they are “peaceful” by reputation.

Suitable tankmates

• Other micro rasboras and small danios (e.g. Danio erythromicron)
• Small, peaceful tetras (in larger aquariums)
• Dwarf shrimp such as Neocaridina or Caridina (with caution regarding fry predation)
• Small snails: Neritina, Clithon, etc.
• Very small, calm labyrinth fish like sparkling gourami (Trichopsis pumila), in larger and more structured tanks

When mixed with shrimp, adult Boraras usually do not cause major problems, although they may eat freshly hatched shrimplets. Dense moss and fine plants can help shrimplets find hiding places and increase survival.

Tankmates to avoid

• Any medium or large fish, even if peaceful (e.g. angelfish, larger gouramis)
• Active, fast species that may outcompete Boraras for food
• Fin-nippers that may harass delicate fish
• Large or aggressive species of shrimp and crayfish

Many aquarists decide to keep neon blue rasboras in a species-only aquarium. This solution has several advantages: fish are more confident, coloration is more intense, and behavior can be observed without disturbance. A larger shoal in a well-designed, plant-rich tank often becomes the focal point of the entire room.

Breeding Boraras in the Aquarium

Breeding neon blue rasboras is not very difficult, but requires attention to detail and patience. These fish do not exhibit parental care and scatter their eggs among plants, so successful rearing of fry depends on providing safe conditions.

Sexing

• Males are usually slimmer, more intensely colored, with more contrasting markings
• Females are slightly rounder, especially in the belly area when full of roe
• In some species, males show more intense blue or red sheen

Breeding aquarium

For breeding attempts, prepare a small aquarium (15–25 liters) with:

• Sponge filter with very gentle flow
• Bottom covered with mosses or fine-leaved plants
• Possibly a mesh or marbles to protect eggs from being eaten
• Soft, slightly acidic water, well conditioned and matured

Introduce a group of well-conditioned adults (for example, 2 males and 4 females) and feed abundantly with live and frozen foods for several days. Spawning can occur spontaneously, often in the morning, with fish scattering eggs among plants.

Egg and fry care

After noticing spawning behavior or eggs, adults should be removed to prevent them from eating the clutch. At temperatures around 25 °C, eggs hatch within 24–36 hours. The fry are very tiny and at first will feed on microscopic organisms in the water and on plant surfaces.

To increase survival rate, provide:

• Infusoria cultures (paramecium, etc.)
• Liquid fry foods
• Later, freshly hatched brine shrimp and microworms

Because fry are sensitive to water quality, small, frequent water changes using water with identical parameters are essential. Successful breeding is a rewarding experience and allows aquarists to maintain a stable population without relying on wild-caught imports.

Common Mistakes and How to Avoid Them

Caring for neon blue rasboras is not extremely difficult, but their small size makes them less forgiving of certain errors. Avoiding a few typical mistakes will significantly improve their well-being.

Placing them in an uncycled aquarium

Boraras do not tolerate the presence of ammonia and nitrite even in low concentrations. Introducing them into a newly set up tank, before the completion of the nitrogen cycle, almost always ends in health problems. Before adding fish, make sure the aquarium is fully cycled, which can be easily monitored with test kits available from MB Store.

Too strong a current

Oversized filters with intense flow cause chronic stress. Fish hide in corners and under leaves instead of swimming freely. If necessary, reduce the flow, use a spray bar or deflect water against the glass to soften the current.

Inappropriate tankmates

Even “semi-peaceful” fish many times larger than Boraras may see them as easy snacks. It is always better to plan a community based on the smallest and gentlest species, or choose a species-only tank that highlights the schooling behavior of neon blue rasboras.

Overfeeding

Because they are small, it is easy to overestimate how much food they actually need. Excess food decomposes, leading to deterioration of water quality and diseases. Small portions two times a day, with careful observation of how quickly food is consumed, are much safer.

Neglecting water changes

Nano aquariums react quickly to pollution. Accumulation of nitrates and organic waste is insidious and may not be visible at first glance. Regular water changes and occasional parameter checks are essential to keep the environment stable and safe.

Why Neon Blue Rasboras Are Ideal for Modern Aquarists

Neon blue rasboras perfectly fit the trend of small, carefully designed aquariums that can be placed almost anywhere: on a desk, in a living room, or in reception areas. Their advantages are especially appreciated by aquarists who value aesthetics, natural behavior and subtle beauty.

• They require relatively little space, while still thriving in a well-thought-out layout
• They present best in densely planted aquariums with roots and leaves
• Their natural schooling behavior is captivating and relaxing to watch
• They encourage a careful, responsible approach to fishkeeping

For aquarists who want to build such an environment, MB Store provides not only a wide selection of suitable aquariums and aquarium equipment, but also substrates, decorative roots, leaves, conditioners and high-quality foods for nano fish. With thoughtful planning and the right gear, even a relatively small tank can become a fully functional, stable ecosystem, and neon blue rasboras – the shimmering heart of that underwater world.

FAQ – Neon Blue Rasbora (Boraras spp.)

Are neon blue rasboras suitable for beginners?
Yes, provided the beginner is willing to learn the basics of the nitrogen cycle and regular maintenance. These fish are hardy enough for a carefully prepared tank, but do not tolerate an uncycled aquarium or sudden parameter swings. In a stable, planted setup they are calm, resilient and rewarding.

How many neon blue rasboras should I keep together?
They are schooling fish and should be kept in groups of at least 8–10 individuals, preferably more. A larger shoal feels safer, shows more natural behavior and more intense coloration. In a 30–40 liter aquarium, a group of 15–20 Boraras creates an impressive, lively display without overcrowding.

Can I keep neon blue rasboras with shrimp?
Yes, in many setups they coexist well with dwarf shrimp. Adult shrimp are usually safe, but Boraras may eat newly hatched shrimplets. If breeding shrimp is a priority, provide lots of moss and fine plants as hiding places. Regular feeding and good structure help both species thrive together.

Do neon blue rasboras need a heater?
In most homes, yes. They prefer stable temperatures around 24–25 °C and do not react well to frequent fluctuations. If room temperature drops below 22 °C or varies significantly between night and day, a reliable heater with thermostat is strongly recommended to maintain optimal conditions.

How long do neon blue rasboras live?
In well-maintained aquariums with stable water parameters and proper diet, neon blue rasboras typically live 3–5 years. Good filtration, regular water changes, a varied diet including frozen or live foods, and avoiding stress from inappropriate tankmates are the keys to reaching the upper end of this lifespan.