Dwarf Rasbora (Boraras maculatus)

Dwarf Rasbora (Boraras maculatus)

Dwarf Rasbora, Boraras maculatus, is a tiny Southeast Asian shoaling fish for planted nano aquariums, blackwater layouts and calm community tanks. It is also sold as Pygmy Rasbora, Spotted Dwarf Rasbora or Dwarf-spotted Rasbora. Older trade copy may still show the name Rasbora maculata; this listing uses the current accepted aquarium identity, Boraras maculatus, while keeping the familiar common names that fishkeepers actually search for.

This is not a large centrepiece fish. Its beauty comes from scale, movement and group behaviour: warm copper-red colour, dark side spots, fine transparent fins and a delicate midwater shimmer. A single fish is easy to overlook, but a settled group moving through moss, stems and floating roots can become one of the most natural-looking displays in a nano aquarium.

Natural Habitat and Care Style

FishBase records Boraras maculatus from quiet forest streams with slow-flowing acidic water, and lists the species at about 2.5 cm. That habitat clue matters. These fish are built for calm, shallow, plant-rich water rather than bright, turbulent community tanks. In the aquarium they settle best when the layout gives cover above, around and behind the shoal.

Think of the tank as a shaded forest-edge layout: dark substrate, fine-leaved plants, moss, driftwood, leaf litter and floating plants. You do not need to turn the aquarium into a tea-coloured blackwater tank, but the same principles help: soft light, gentle flow, stable water and plenty of safe places to pause. When those pieces are right, the fish hold colour better and spend more time in open water.

Best Aquarium Setup

A mature 40 litre or larger aquarium is a sensible starting point for a small group. They are physically tiny, but tiny fish are not automatically easy in tiny tanks; water chemistry swings faster in small volumes. A larger planted nano tank gives the group more swimming space and gives you more stability.

Use gentle filtration, preferably a sponge filter or a baffled outlet. Strong current can push the shoal into corners and make feeding difficult. Leave open midwater space at the front, with planting and roots behind it, so the fish can retreat and return. A tight-fitting lid is still useful on small aquariums, especially during maintenance or acclimation.

Water Parameters

Aim for warm, soft, slightly acidic water. A useful target range is 24-27C, pH about 5.0-6.8 and low to moderate hardness. FishBase gives an acidic pH range and tropical temperatures; aquarium care references broadly agree that soft, stable water is the safer long-term direction.

Do not chase a number every day. Stability is more important than forcing the pH down with sudden chemical changes. Use mature biological filtration, avoid over-cleaning the filter, and make small regular water changes. If your tap water is hard, consider whether this species is the right fit before ordering, or prepare a stable soft-water method first.

Feeding

Dwarf Rasboras are micropredators/omnivores with very small mouths. Feed tiny foods that spread through the water column: quality micro pellets, powdered or crushed flake, cyclops, daphnia, baby brine shrimp, grindal worm and other fine frozen or live foods. Colour and condition improve when the diet is varied, especially with small frozen or live foods.

Small portions once or twice daily are better than one heavy feed. In mixed communities, watch that food actually reaches the rasboras. Larger fish often grab the obvious food first, while the tiny shoal waits in cover. Feed the bigger fish at one end and add fine food near plants or floating cover so the group can eat without being pushed away.

Temperament and Tank Mates

This is a peaceful shoaling fish. Keep at least six, and ideally ten or more, so the group feels secure and behaves naturally. A larger group also makes the colour, movement and confidence easier to appreciate. They are not fin nippers, plant destroyers or territorial fish; their main weakness is being too small and gentle for rough company.

Good tank mates are small, calm species with similar water preferences: other tiny rasboras, ember tetras, pygmy corydoras, small otocinclus and peaceful dwarf shrimp colonies with caution around newly hatched shrimplets. Avoid large, fast, boisterous or predatory fish. Even if a tank mate cannot swallow an adult rasbora, constant chasing or food competition can keep the group hidden.

Visual Identification

A healthy Dwarf Rasbora should look slim, alert and active, with clear eyes, intact fins and a visible dark side spot. Colour varies with age, mood, lighting and tank setup. Fish kept in pale, exposed tanks may look washed out; fish in planted, shaded aquariums usually show warmer orange-red tones and sharper markings.

They are sometimes confused with other Boraras species such as Chili Rasbora or Phoenix Rasbora. The exact patterning can be subtle, so the scientific name and supplier source photo are important. The listing title avoids the old forced "X Dwarf" wording because that came from trade-pack phrasing, not a natural product name.

Acclimation and First Week

Because these fish are small and soft-water oriented, the first week matters. Dim the lights, float and acclimate slowly, and release them into a calm area with plants nearby. Do not add them to a new uncycled aquarium. A mature tank with stable temperature and low nitrate is far safer than a freshly set-up nano display.

Have tiny foods ready before the fish arrive. If the group hides at first, offer a very small amount near cover and step back. Confidence usually improves once the shoal learns the feeding routine and tank mates ignore them.

Breeding Notes

In mature planted aquariums this species may spawn among fine plants, moss or dense roots. Eggs are scattered rather than guarded, so most fry are eaten in a community tank. A dedicated breeding setup uses very soft acidic water, fine-leaved plants or spawning mops, gentle air-driven filtration and tiny first foods for fry such as infusoria before moving on to newly hatched brine shrimp.

For most keepers, breeding should be seen as a bonus. The priority is a settled shoal, stable water and food small enough for every fish to take.

Health and Prevention

Most problems come from stress, unstable water or unsuitable tank mates. Warning signs include clamped fins, fading colour, rapid breathing, isolation from the group or refusal to feed. Check temperature, ammonia, nitrite and nitrate before reaching for medication, because tiny fish can react badly to both poor water and heavy treatments.

Prevention is simple but strict: quarantine new fish where possible, keep the aquarium mature, avoid sudden parameter swings, feed tiny varied foods and choose calm tank mates. A peaceful setup does more for this species than any single supplement.

Who This Fish Suits

Choose Dwarf Rasbora if you want a delicate nano shoal for a mature planted aquarium, not a fish for a new, bright, high-flow setup. It suits aquarists who enjoy subtle behaviour, blackwater-style aquascaping and peaceful communities built around small species.

This listing is currently in stock. First-time customers can use WELCOME10 where eligible, and live fish orders are covered by our Live Arrival Guarantee when the delivery instructions are followed. We still recommend preparing the aquarium before ordering: a cycled tank, covered acclimation area and tiny foods make the first week much smoother.

Quick Care Summary

• Scientific name: Boraras maculatus
• Common names: Dwarf Rasbora, Pygmy Rasbora, Spotted Dwarf Rasbora
• Adult size: about 2-2.5 cm
• Minimum group: 6+, best in 10+
• Tank size: 40 litres or more for a stable planted shoal
• Temperature: 24-27C
• pH: soft and acidic preferred, about 5.0-6.8
• Temperament: peaceful, shy with large tank mates
• Diet: tiny micro foods, frozen/live foods and fine prepared foods