Harlequin Rasbora Care Guide: Trigonostigma heteromorpha for UK Aquarists

The Harlequin Rasbora (Trigonostigma heteromorpha) is one of the most recognisable and widely kept freshwater shoaling fish in the world, and a firm favourite in the UK hobby for good reason. We stock Harlequin Rasboras in our UK shop for tracked delivery. This is the complete harlequin rasbora care guide I write and update based on years of keeping this species — covering everything from harlequin rasbora tank size and water chemistry to harlequin rasbora tank mates, diet, their unique breeding behaviour, and the common mistakes I see beginners make. Every claim in this guide is backed by cited sources at the bottom — FishBase^[1] for scientific data, Seriously Fish^[2] for hobbyist-verified care information, and my own notes from keeping the species across multiple tank setups.

Harlequin Rasbora are instantly identifiable by the bold black triangular patch on the rear half of the body set against a warm copper-orange base colour. That distinctive marking — shaped like a lamb chop or broad wedge — is why some older references call them the Red Rasbora or Pork Chop Rasbora. Trigonostigma heteromorpha creates a moving ribbon of warm metallic colour when kept in a proper shoal, which is why this classic rasbora fish remains one of the best choices for planted community aquariums in the UK. Adult harlequin rasbora size reaches around 4-5 cm, harlequin rasbora lifespan is typically 5-6 years with good care, and their undemanding nature makes them a strong choice for anyone looking for beginner tropical fish UK setups. They are especially popular as a best shoaling fish for beginners UK option because they settle quickly, stay peaceful, and suit a huge range of tank mates.

In this detailed harlequin rasbora care guide, you will learn the ideal harlequin rasbora temperature, harlequin rasbora tank size, harlequin rasbora water parameters, feeding routine, compatibility, and their remarkable breeding biology. We also answer common questions such as how many harlequin rasboras should be kept together, what do harlequin rasboras eat, and harlequin rasbora vs neon tetra. For aquarists building a peaceful display, these fish bring warmth, movement, and coordinated shoaling behaviour that transforms an ordinary planted tank into a living Southeast Asian biotope.

Classification

• Order: Cypriniformes

• Family: Cyprinidae

• Genus: Trigonostigma

  Trigonostigma heteromorpha was formerly placed in the genus Rasbora, but taxonomic revision moved it to Trigonostigma along with a handful of close relatives that share the distinctive dark body marking. Within the hobby, it sits alongside species such as the lambchop rasbora (T. espei) and glowlight rasbora (T. hengeli), each with a slightly different body shape and marking pattern. The Harlequin Rasbora has earned its place as a classic tropical fish for community tank setups because it combines manageable size, striking colour, and genuinely peaceful temperament with one of the most interesting breeding strategies of any common aquarium fish.

Where Do Harlequin Rasboras Come From? Natural Habitat Explained

The natural Trigonostigma heteromorpha habitat spans Southeast Asia, with wild populations found across the Malay Peninsula, southern Thailand, Singapore, and the Indonesian island of Sumatra. In the wild, this harlequin rasbora species lives in slow-moving forest streams, peat swamps, and shaded tributaries where the water is stained dark amber by decaying leaf litter and humic acids. These habitats are typically dimly lit, soft, acidic, and densely vegetated, which explains why a dark, planted aquarium with tannin-stained water often brings out the best colour and confidence in harlequin rasbora fish.

Wild fish spend much of their time in loose to tight shoals beneath overhanging vegetation, using the dappled shade as cover. That is why proper harlequin rasbora group size matters so much in captivity. In small groups they become nervous, pale, and spend too long hiding. In a larger shoal of 10 or more they display their full copper-orange colour, tighter coordinated movement, and confident midwater presence. This is one reason they remain a top shoaling fish UK choice for peaceful planted aquariums.

In nature, Trigonostigma heteromorpha feeds on small insects, worms, zooplankton, and crustaceans from the water column and leaf surfaces. That natural feeding pattern explains why a varied harlequin rasbora diet with both prepared and frozen foods works best. The species is adapted to stable, warm water conditions rather than rapid changes, so careful acclimation and consistent maintenance matter more than hitting an exact pH number.

You may see hobbyists compare this fish with the lambchop rasbora or espei rasbora, which are slimmer and have a narrower body marking. The key habitat difference between the three Trigonostigma species is subtle — all prefer soft, acidic water and similar temperatures. However, the Harlequin is the largest and hardiest of the three, making it the best option for beginners. They are not fish for bowls, jars, or unfiltered containers — they need a mature, filtered, heated aquarium with stable chemistry and room to swim.

Expert Tip

Mimicking the natural habitat of Harlequin Rasboras with dark substrate, driftwood, broad-leaved plants like Cryptocoryne, and subdued lighting dramatically improves colour and reduces stress. Adding Indian almond leaves or alder cones to gently tint the water can bring out the full copper richness of the body colour and encourage tighter shoaling within days.

How to Set Up the Perfect Tank for Harlequin Rasboras

A thoughtful harlequin rasbora tank setup is the difference between a pale, scattered group and a confident, glowing shoal. The minimum harlequin rasbora tank size is 60 litres, but that should be treated as a starting point for a modest group. For a stronger display and better social dynamics, a 90-120 litre aquarium is far better, especially if you want a harlequin rasbora group of 12 or more in a mixed Southeast Asian community.

Tank Size Requirements

The most common question is how many harlequin rasboras can be kept together. The practical answer depends on footprint, filtration, and tank mates, but the harlequin rasbora minimum group size should be 8, ideally 10-12. A small group of 4-6 survives but never thrives. In a 60-litre aquarium, keep stocking simple and focus on one proper shoal. In larger tanks, buying a group of 10-15 makes far more sense because these fish look best in numbers — the coordinated movement of a proper shoal is one of the most beautiful sights in a planted aquarium.

For a dedicated species display, a 60-litre tank can hold a lively group of 10-12 comfortably. For a harlequin rasbora community tank setup, aim bigger so each species has space and the rasboras have enough midwater swimming room to display natural behaviour.

Water Parameters

The ideal temperature for harlequin rasboras is usually 24-27°C, though the full Trigonostigma heteromorpha temperature range is 22-28°C. This slightly warmer preference is important when choosing tank mates — they pair well with other Southeast Asian species that enjoy similar warmth. Stable harlequin rasbora temperature matters more than chasing an exact number, so avoid daily swings.

The recommended harlequin rasbora pH range is 5.0-7.5, with most captive-bred fish doing well around pH 6.0-7.0. Harlequin rasbora water hardness should stay soft to moderately soft, ideally 1-12 dGH. These are the core harlequin rasbora water parameters to aim for: temperature 24-27°C, pH slightly acidic to neutral, and low to moderate hardness. If you keep them within those limits and maintain clean water, harlequin rasbora care becomes straightforward.

60L+ Minimum tank

24-27°C Ideal temperature

5.0-7.5 pH range

1-12 dGH Hardness

Filtration

Harlequin Rasboras appreciate clean, oxygenated water with gentle to moderate flow. A sponge filter works well in smaller or breeding systems, while a compact internal or hang-on-back filter suits larger displays. Strong current is not ideal because these fish naturally occupy calmer water beneath vegetation. Good filtration is a core part of harlequin rasbora disease prevention because poor water quality triggers stress-related problems quickly in soft-water species.

Substrate

Dark sand or fine dark gravel is the best choice. Dark substrate makes the copper-orange body colour glow and helps the fish feel secure. This is especially effective in a planted aquascape harlequin rasbora layout where the warm tones of the fish contrast beautifully against green plants and brown driftwood. Pale or white substrate can make the fish look washed out and more nervous.

Plants & Decor

A harlequin rasbora planted aquarium setup is one of the best ways to keep this species. Use clumps of broad-leaved Cryptocoryne species, fine-leaved stems, Java fern, mosses, floating plants, and open swimming lanes. Dense planting around the edges with a clear central corridor creates the best shoaling effect. Broad leaves are particularly important if you plan to breed — Harlequin Rasboras deposit their eggs on the undersides of leaves, a behaviour unique among common aquarium fish. Driftwood and leaf litter complete the Southeast Asian look and provide beneficial tannins.

Lighting Requirements

Moderate to subdued lighting works best and most closely matches their natural forest-stream habitat. Very bright lighting without plant cover may make them skittish, while softer light enhances the metallic copper sheen that makes this species so attractive. Floating plants are an excellent way to diffuse overhead light naturally. Aim for 6-8 hours daily in newer tanks and 8-10 hours in mature planted systems.

Pro Tip

Always cycle the tank for 4-6 weeks before adding Harlequin Rasboras. While they are hardier than many soft-water species once settled, newly shipped fish can react badly to ammonia or nitrite spikes in an immature tank. Seeding the filter with media from an established aquarium speeds up the process considerably.

What Do Harlequin Rasboras Eat? Complete Feeding Guide

If you have ever asked what do harlequin rasboras eat, the short answer is: almost anything small enough to fit in their mouths. In the wild, Trigonostigma heteromorpha feeds on tiny insects, crustaceans, worms, and zooplankton from the water column and leaf surfaces. In the aquarium, a balanced harlequin rasbora feeding guide should include quality micro pellets, fine flakes, and regular frozen or live foods. A good harlequin rasbora diet supports colour, immune health, and breeding condition.

Staple Foods

The best daily harlequin rasbora food is a fine tropical flake or slow-sinking micro pellet suited to midwater feeding. Because these are modestly sized cyprinids with relatively small mouths, oversized granules are often ignored or spat out. Feed what they can finish in 30-60 seconds, twice daily.

Supplemental Foods

To improve condition and bring out the best colour, offer frozen daphnia, cyclops, baby brine shrimp, or finely chopped bloodworm once or twice a week. These foods are especially useful before attempted harlequin rasbora breeding. The copper-orange body colour intensifies noticeably when the diet includes regular frozen and live foods rather than flakes alone.

Treats & Conditioning Foods

Live baby brine shrimp and microworms are excellent conditioning foods for bringing adults into spawning condition. They help females fill out with roe and encourage stronger spawning responses. If you keep a larger group of 12 or more, varied feeding also reduces competition at feeding time and ensures shyer individuals maintain weight.

Feeding Frequency & Portion Control

Feed once or twice daily in small portions. A practical harlequin rasbora care guide rule is little and often rather than one heavy meal. In community tanks, watch that faster or more aggressive feeders do not outcompete them — Harlequin Rasboras are confident feeders but can be pushed aside by larger or bolder species.

For customers looking at harlequin rasbora for sale, it is worth knowing that newly arrived fish may eat lightly for the first day or two as they settle. Once established, healthy fish should feed eagerly and come to the front of the tank at feeding time. If you plan to buy harlequin rasboras UK for a new tank, have suitable food ready before arrival. This is one of the easiest parts of harlequin rasbora care, but consistency matters.

Feeding Warning

Overfeeding causes ammonia spikes, cloudy water, and stress. Harlequin Rasboras are moderate-sized fish but even a small excess can foul a lightly stocked tank over time. Remove uneaten food after a couple of minutes and keep portions modest.

Harlequin Rasbora Appearance: Colours, Markings & Sexing

The classic harlequin rasbora look is unmistakable: a deep, laterally compressed body with a warm copper-orange to pinkish-orange base colour, overlaid with a bold black triangular patch that starts roughly at the dorsal fin and tapers to a point at the base of the tail. This wedge-shaped marking — broader at the front and narrower at the rear — is the defining feature and gives the fish its common name. Adult harlequin rasbora size is usually around 4-5 cm, making them substantial enough to be visible in larger aquariums while still suitable for modest setups.

Under subdued light with a dark background, the copper body takes on an almost metallic sheen, which is why this species looks so spectacular in planted aquascapes with driftwood and leaf litter. In groups, the effect is stunning — a moving cloud of warm copper punctuated by crisp black triangles. The fins are mostly transparent with a faint orange or amber wash, and the eye has a golden-copper iris that adds to the overall warmth of the fish.

Sexing Harlequin Rasboras becomes possible as adults mature. Males tend to be slimmer, with the black triangular marking having a more defined, sharply pointed lower edge. Females are typically fuller-bodied, especially when carrying eggs, and the lower edge of the black patch is usually slightly more rounded or straight rather than sharply angled. This difference is subtle in juveniles but becomes more obvious in well-conditioned adults and is useful for selecting breeding groups.

Compared with the lambchop rasbora (T. espei), the Harlequin has a deeper body and a much broader, more triangular black patch — the lambchop's marking is narrower and more elongated. The glowlight rasbora (T. hengeli) is the smallest and most subtly marked of the three. All three species are sold in the UK hobby, but the Harlequin remains the most popular because of its bolder colour and slightly hardier constitution.

What Fish Can Live With Harlequin Rasboras? Compatibility Guide

The harlequin rasbora behaviour profile is peaceful, social, and non-territorial. They are ideal harlequin rasbora tank mates for calm community fish that share similar water conditions and will not view them as food. Because they are moderate-sized and non-aggressive, avoid large predatory cichlids and boisterous species that will outcompete them. A harlequin rasbora community tank setup works best when every fish is selected around the same temperament and water parameter preferences.

Ideal Tank Mates

Good companions include other peaceful cyprinids, small tetras, Corydoras catfish, Otocinclus, kuhli loaches, dwarf gouramis, and cherry barbs. For a Southeast Asian biotope, pairing them with Corydoras, kuhli loaches, and a honey gourami centrepiece creates a harmonious community. For aquarists who prefer a South American mixed-origin display, they combine beautifully with neon tetras, cardinal tetras, and ember tetras — all share a preference for soft, slightly acidic water.

One of the best harlequin rasbora tank mates combinations is with a betta. This is widely regarded as one of the most successful betta community pairings in the hobby. Harlequin Rasboras are not fin-nippers, they occupy the mid-water column rather than competing for surface space, and their warm copper colour complements most betta varieties beautifully. In a planted 60-litre or larger tank, a group of 8-10 Harlequin Rasboras with a single betta creates a stunning, peaceful display. The rasboras provide movement and activity while the betta remains the centrepiece. This combination works because the rasboras are large enough not to be mistaken for food, confident enough to ignore the betta, and calm enough not to trigger aggression.

Species to Avoid

Avoid fin-nippers and any fish large enough to swallow them. Fast, boisterous species like tiger barbs can stress them and outcompete them for food. Large cichlids, including mature angelfish, may prey on them or dominate the tank. Aggressive barb species are also best avoided in smaller aquariums.

Community Tank Stocking Examples

For a 60-litre planted tank, one harlequin rasbora group of 10 makes a strong starting point. In a 90-litre setup, a group of 12-15 with Corydoras bottom dwellers creates a beautiful, active display. For a 120-litre Southeast Asian community, combine 12 Harlequin Rasboras with 6-8 kuhli loaches, a pair of honey gouramis, and a group of Corydoras for a biotope-inspired layout with activity at every level of the water column.

Compatibility with Invertebrates

Adult cherry shrimp and amano shrimp coexist well with Harlequin Rasboras. Very small shrimplets may be eaten opportunistically, but in a well-planted tank with plenty of cover, shrimp breeding colonies can sustain themselves alongside a rasbora shoal. Nerite snails and other snails are completely safe.

Compatibility Tip

When introducing Harlequin Rasboras to a tank with an existing betta, add the rasboras in a group of 8 or more at once. A confident shoal is far less likely to trigger a betta's territorial response than adding fish one or two at a time.

Understanding Harlequin Rasbora Shoaling Behaviour

Harlequin rasbora behaviour is one of the main reasons people love this species. They are active midwater shoalers that spend much of the day moving as a coordinated group, especially in tanks with open swimming lanes between planted areas. When kept in a proper shoal of 10 or more, they show the classic synchronised movement — turning, pausing, and accelerating as a single unit — that makes them one of the best shoaling fish for UK aquariums.

Unlike some schooling fish that only tighten formation when stressed, Harlequin Rasboras maintain a relatively cohesive group even when relaxed. They drift apart slightly during feeding and exploration but reform into a loose shoal repeatedly throughout the day. When startled, the group snaps into a tight ball and moves as one — a behaviour that is both functional (predator confusion) and visually spectacular in the home aquarium.

They are most confident under moderate lighting with dark decor and plant cover. If they spend long periods hiding or hugging the back glass, check group size first — this is almost always the cause. A group of 4-5 will behave completely differently from a group of 12. Lighting intensity and tank mate temperament are secondary factors. For anyone wanting a classic tropical fish for community tank use, this species offers exactly the kind of coordinated, lively movement that makes an aquarium feel alive.

Activity peaks in the morning and evening, with a slightly more settled period through the middle of the day. They occupy the middle third of the water column primarily, occasionally moving higher during feeding or lower to explore leaf litter and decor. This midwater preference is one reason they combine so well with bottom-dwelling Corydoras and surface-oriented gouramis or bettas — each species occupies its own zone.

How to Breed Harlequin Rasboras: Complete Breeding Guide

Harlequin rasbora breeding is one of the most fascinating spawning behaviours you will encounter in a community fish. Unlike most egg-scattering cyprinids, Harlequin Rasboras deposit their eggs on the underside of broad leaves — a behaviour that is unique among commonly kept aquarium rasboras and makes breeding this species a genuinely rewarding project for the dedicated hobbyist.

Breeding Setup

Use a separate 30-40 litre breeding tank with very soft water (2-6 dGH), a pH of 5.5-6.5, and a temperature of 26-28°C — slightly warmer than normal maintenance temperature. The key furnishing is broad-leaved plants: Cryptocoryne species are the traditional and most successful choice, but large Anubias leaves or even plastic broad-leaved plants can work. The plants should be positioned so there are accessible undersides at mid-water level. Dim lighting and a dark substrate help the fish feel secure enough to spawn.

Spawning Behaviour

Condition the adults with live and frozen foods for 1-2 weeks before introducing them to the breeding tank. When ready, the male begins courting by displaying alongside the female with flared fins and intensified colour. The pair then positions themselves upside down beneath a broad leaf. The female presses her belly against the leaf underside and deposits a small cluster of adhesive eggs, which the male immediately fertilises. This inverted spawning is repeated several times across different leaves over the course of a morning. A single spawning session can produce 80-300 eggs.

This upside-down, leaf-surface spawning behaviour is remarkable because it means the eggs are sheltered from below, protected from most bottom-dwelling egg predators, and hidden from above by the leaf itself. It is a strategy that works beautifully in the wild among dense vegetation and leaf litter.

Egg Care & Hatching

Remove the adults after spawning is complete — they do not guard the eggs and may eat them if left in the breeding tank. The eggs are semi-transparent and adhesive, clinging to the leaf surface. Under suitable conditions (soft, warm water around 27°C), eggs hatch in approximately 18-24 hours. The newly hatched fry remain attached to the leaf surface as yolk-sac fry for another 24-48 hours before becoming free-swimming. Keep the tank dim during this period and maintain impeccable water quality.

Fry Care & Growth

Start free-swimming fry on infusoria or commercial liquid fry food for the first week, then graduate to newly hatched baby brine shrimp and microworms as they grow. Growth is steady but not rapid — expect the fry to reach recognisable juvenile size with the beginnings of the black triangular marking at around 6-8 weeks. Regular small water changes with aged, soft water are essential during the growth phase. Avoid strong filtration that could suck up tiny fry — a gentle sponge filter is ideal.

Common Breeding Challenges

The main challenges are achieving soft enough water for successful fertilisation, preventing adults from eating eggs before you can remove them, and raising the tiny fry through their first week of free-swimming life. Many failures happen because the water is too hard — in hard water areas of the UK, using RO water remineralised to 2-4 dGH is often necessary for breeding success. Without suitably soft water, eggs may fail to develop even if the spawning behaviour occurs normally.

Advanced Breeding Tip

For the best hatch rates, use very soft RO water remineralised to just 2-4 dGH and acidified to pH 5.5-6.0 with Indian almond leaves or peat extract. The leaves serve double duty — they acidify the water and provide spawning surfaces. Introduce the conditioned pair in the evening and spawning will often occur the following morning as light levels gradually increase.

Common Health Problems in Harlequin Rasboras & How to Prevent Them

Healthy Harlequin Rasboras are active, alert, and tightly grouped, with bright copper-orange colour, clear eyes, and smooth fins. Poorly kept fish may become pale, isolate from the group, clamp their fins, or breathe rapidly. Good harlequin rasbora disease prevention starts with stable water, proper group size, appropriate temperature, and careful acclimation of new arrivals.

Signs of a Healthy Harlequin Rasbora

Look for vibrant copper-orange body colour, a crisp black triangular marking, smooth coordinated swimming, eager feeding response, and relaxed shoaling throughout the day. A good harlequin rasbora lifespan of 5-6 years depends on these basics being maintained consistently rather than corrected only when problems appear.

Common Diseases & Symptoms

Common issues include ich (white spot disease), bacterial infections, fin damage from nipping tank mates, and stress-related losses after transport. Fading colour or erratic swimming are not diagnoses on their own, but they are early warning signs that mean you should test water parameters immediately and inspect the fish closely.

Harlequin Rasboras are generally hardy once established, but they can be sensitive during the first week after shipping. Disease can progress quickly in small fish, so early detection and treatment matter. Quarantine all new arrivals and act promptly on any symptoms.

Treatment Options

Use a separate hospital tank where possible to avoid medicating the entire display. Increase aeration, perform partial water changes, and choose treatment based on the actual symptoms rather than guessing. If invertebrates such as shrimp are present in the display tank, always check medication safety before adding anything — many common treatments are lethal to shrimp.

Prevention Tips

Keep a proper shoal of 8 or more, avoid aggressive tank mates, feed a varied diet, and maintain stable harlequin rasbora water parameters. This is why a mature planted tank is often ideal — the biological stability of an established system with live plants provides the consistent conditions these fish need to stay healthy and resilient.

Quarantine Procedures

Quarantine new fish for 2-4 weeks in a separate heated, filtered tank. Observe feeding response, faeces, skin condition, and swimming behaviour daily. This is especially important if you buy harlequin rasboras online UK or mix shipments from different sources. Never add new fish directly to an established display without quarantine.

Medication Warning

Never use copper-based medications in tanks with shrimp or other sensitive invertebrates. Copper can be lethal to shrimp even at low concentrations. Always check treatment compatibility before dosing a community tank.

Why Buy from Tropical Fish Co?

When customers search harlequin rasbora UK, harlequin rasbora for sale UK, or buy harlequin rasboras online UK, they are usually looking for more than price alone. They want active fish with bright copper colour and strong shoaling behaviour — fish that will immediately enhance a planted community tank. This listing is designed around that reality: Harlequin Rasboras look and behave best when purchased as a proper group rather than as a token pair.

Our Harlequin Rasboras are selected for strong copper-orange body colour, crisp black triangular markings, and active shoaling behaviour before dispatch. They are held, observed, and fed on a suitable small-particle diet so they are already accustomed to prepared foods. For customers planning a shoal purchase, that matters because settled fish integrate far more smoothly into established aquariums than stressed, newly imported individuals.

Each order is packed for live fish transport with insulated materials, secure fish bags, and seasonal heat packs when needed. Tracked delivery helps reduce time in transit, and careful packing minimises temperature swings. If you are comparing harlequin rasbora price UK or cheapest harlequin rasbora UK, remember that condition on arrival and group quality are just as important as the headline number — a healthy group that settles quickly saves you far more in the long run than a cheap batch that arrives stressed.

For aquarists building a Southeast Asian planted community, we can help you choose compatible species and sensible stocking levels. Order your Harlequin Rasboras today with confidence and build the kind of planted community tank these fish were made for.

Why Choose Tropical Fish Co for Harlequin Rasboras

• Selected as active shoaling fish with strong copper-orange colour, not random leftover stock
• Held and monitored before dispatch to ensure strong feeding response on prepared foods
• Packed specifically for cyprinids with insulated materials and seasonal heat protection

You Might Also Like

To build a fuller Southeast Asian community, consider pairing your Harlequin Rasboras with bottom-dwelling species like Corydoras or kuhli loaches that occupy a different zone of the tank. For a warm-toned display, cherry barbs complement the copper hues beautifully. If you want a contrasting cool-toned shoal alongside them, neon tetras or cardinal tetras provide stunning blue-red contrast against the rasboras' warm copper-orange. For a betta community centrepiece, a group of 10-12 Harlequin Rasboras is one of the most reliable and visually striking companion choices available.

Answers to the most common questions

Harlequin Rasbora For Sale

We currently have Harlequin Rasboras in stock with tracked UK delivery. Scroll down to the shop block for live prices and add-to-cart.

Harlequin Rasbora Size & Lifespan

Harlequin Rasboras typically reach an adult size of around 4-5 cm and live 5-6 years with good care in a well-maintained aquarium.

Harlequin Rasbora Breeding

Breeding Harlequin Rasboras is possible and uniquely rewarding — they deposit eggs on the underside of broad leaves in an inverted spawning posture. See the breeding section above for full details on water parameters, leaf selection, and fry care.

Harlequin Rasbora Care

Harlequin Rasbora care is considered easy. They need a tank of at least 60 litres, temperature of 22-28 °C, and pH in the 5.0-7.5 range. Keep in groups of 8 or more. See the full care specs above.

Harlequin Rasbora Tank Mates

Harlequin Rasboras are among the most peaceful community fish available. They pair exceptionally well with bettas, other small rasboras, tetras, Corydoras, kuhli loaches, dwarf gouramis, and cherry barbs. See the full compatibility section above.