Blueberry Tetra

Quick summary

The Blueberry Tetra is a striking but hard to find soft water tetra best suited to hobbyists who can source stable, slightly acidic water and keep a group of at least six to twelve fish in a well-planted 60 litre or larger tank. It is not especially difficult to care for once acquired, but its scarcity in the trade and moderate breeding difficulty make it more of a fish for experienced keepers than true beginners.

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In this guide:

• Introduction
• Quick Stats
• Appearance
• Natural Habitat
• Tank Size and Setup
• Water Parameters
• Filtration and Equipment
• Diet and Feeding
• Behaviour and Temperament
• Tank Mates
• Breeding
• Common Diseases
• FAQs

Introduction

The Blueberry Tetra (Hyphessobrycon wadai) is a strikingly beautiful small characin that has captured the attention of aquarists seeking something a little different from the more commonly available tetras. First scientifically described in 2016 by Marinho, Dagosta, Camelier and Oyakawa, this species hails from the upper Rio Tapajos drainage in Mato Grosso state, Brazil. Its deep, iridescent blue colouration – reminiscent of a ripe blueberry – sets it apart from many of its Hyphessobrycon relatives and has earned it a devoted following among hobbyists who appreciate rare and visually arresting species.

Despite its undeniable appeal, the Blueberry Tetra remains relatively uncommon in the aquarium trade. It appears sporadically through specialist importers and dedicated breeders, and its availability can be unpredictable. This scarcity, combined with its manageable care requirements, makes it a prized addition for experienced hobbyists looking to keep something genuinely special. While it is not a beginner’s fish in terms of sourcing, its husbandry is broadly comparable to other small South American tetras, requiring stable water conditions and a well-maintained aquarium.

This guide covers everything you need to know about keeping the Blueberry Tetra successfully in a home aquarium, from tank setup and water parameters to diet, breeding, and compatible tank mates. Whether you have just acquired your first group or are researching the species before committing to a purchase, the information below will help you provide the best possible care for these stunning little fish.

Appearance

The Blueberry Tetra is a compact, laterally compressed fish with a classic tetra body shape. Adults typically reach between 3 and 4 centimetres in total length, making them a small but visually impactful species. The defining feature of this fish is its extraordinary colouration. Under appropriate lighting, the body displays a deep, saturated blue iridescence that covers the flanks from behind the gill cover to the caudal peduncle. This blue can shift in intensity depending on the angle of light, the fish’s mood, and its overall condition, sometimes appearing as a rich violet-blue and at other times a steely, almost metallic shade.

The dorsal region tends to be somewhat darker, sometimes approaching a deep navy or charcoal, while the ventral area may be slightly paler. The scales catch and reflect light beautifully, giving the fish a shimmering, almost jewel-like quality when it moves through the water column. The fins are generally translucent to slightly tinted, with the dorsal and anal fins occasionally showing a faint wash of colour. A subtle dark marking or humeral blotch may be present behind the operculum, though this is less prominent than in some related Hyphessobrycon species.

The eyes are relatively large and expressive, often showing a reddish or coppery upper iris that contrasts attractively with the blue of the body. Sexual dimorphism is subtle but present. Males tend to be slightly more intensely coloured, particularly when in breeding condition, and may display a marginally slimmer profile. Females are generally a touch rounder in the abdomen, especially when gravid, and their colouration, while still attractive, may be slightly less vivid than that of dominant males.

It is worth noting that the full depth of colour in Blueberry Tetras often does not develop immediately. Newly imported or stressed specimens may appear washed out or greyish, which can be disappointing for new keepers. With time, stable water conditions, a varied diet, and the confidence that comes from being kept in a properly sized group, their colour will develop to its full potential. A dark substrate and subdued lighting, or at least areas of shade, will also significantly enhance the visual impact of their blue colouration.

Natural Habitat

Hyphessobrycon wadai originates from the upper reaches of the Rio Tapajos drainage in the Brazilian state of Mato Grosso. This region lies within the broader Amazon basin and is characterised by a mix of clear and slightly tannin-stained waterways that flow through cerrado (tropical savannah) and transitional forest habitats. The streams and tributaries where this species is found are typically slow to moderately flowing, with substrates composed of sand, fine gravel, leaf litter, and submerged woody debris.

The water in these environments is generally soft and slightly acidic, with a pH that can range from around 5.5 to 6.5 in many locations. Dissolved mineral content is low, resulting in very soft water with minimal carbonate hardness. The presence of leaf litter and decaying organic matter releases tannins and humic acids into the water, giving it a tea-coloured tint in some areas and creating conditions that are mildly antimicrobial.

The riparian vegetation along these waterways provides shade, which keeps light levels relatively low in the aquatic environment. Overhanging branches, submerged roots, and marginal plants create a complex structure that offers shelter and foraging opportunities for small fish like the Blueberry Tetra. In the wild, these tetras likely form loose shoals among the lower and mid-water column, feeding on small invertebrates, insect larvae, and organic detritus.

Understanding this natural habitat is key to replicating appropriate conditions in the aquarium. The preference for soft, slightly acidic water, dim to moderate lighting, and plenty of natural cover should inform your tank design decisions. While captive-bred specimens may tolerate a broader range of conditions than wild-caught fish, providing an environment that echoes their natural habitat will result in healthier, more colourful, and more behaviourally natural fish.

Tank Size and Setup

A minimum aquarium size of 60 litres is recommended for a small group of Blueberry Tetras, though a tank of 80 litres or more will provide a more comfortable environment and allow for a larger shoal. As with most tetras, these fish are best kept in groups of at least six to eight individuals, and a larger group of ten to twelve will produce more natural behaviour and a more impressive visual display. If you intend to keep them in a community setting with other species, scale the tank size upwards accordingly.

The aquascape should aim to replicate the shaded, structurally complex environments these fish inhabit in the wild. A dark, fine-grained substrate – such as dark sand or fine gravel – will help the fish feel secure and will also enhance the visibility of their blue colouration by providing a contrasting backdrop. Lighter substrates can cause the fish to appear pale and may increase their stress levels.

Driftwood and bogwood are excellent additions to a Blueberry Tetra tank. They provide visual barriers, create territories, and release tannins into the water that can help to soften it slightly and create the slightly acidic conditions these fish prefer. Dried Indian almond leaves (Terminalia catappa) or other botanical additions such as oak leaves can further enhance the natural feel of the tank and provide a source of biofilm for the fish to graze upon.

Live plants are highly recommended. Species that thrive in soft, slightly acidic water are ideal choices. Java fern (Microsorum pteropus), various Anubias species, Cryptocoryne species, and floating plants such as Amazon frogbit (Limnobium laevigatum) or red root floater (Phyllanthus fluitans) all work well. Floating plants are particularly valuable as they reduce light levels at the surface, creating the subdued conditions under which Blueberry Tetras show their best colour and most relaxed behaviour.

Avoid an overly sparse or brightly lit setup. While open swimming space should certainly be available in the centre and front of the tank, the periphery should offer dense planting or structural elements where the fish can retreat if startled. A well-planted tank with areas of shade and open water strikes the ideal balance.

Water Parameters

The Blueberry Tetra is a soft water species that will thrive in slightly acidic to neutral conditions. A pH between 5.5 and 7.0 is acceptable, with the sweet spot for most keepers being around 6.0 to 6.5. Very hard or alkaline water should be avoided, as it does not suit this species and may lead to stress, subdued colouration, and increased susceptibility to disease.

Temperature should be maintained between 24 and 28 degrees Celsius. A stable temperature within this range is more important than hitting a specific number. Fluctuations of more than one or two degrees within a short period can stress the fish and should be prevented with a reliable heater and thermostat.

Ammonia and nitrite must always read zero. These compounds are toxic to all freshwater fish, and Blueberry Tetras are no exception. Nitrate should be kept below 20 ppm through regular water changes and good filtration practices. In a well-planted tank with moderate stocking, nitrate accumulation can often be kept very low with weekly water changes of around 20 to 30 per cent.

If your tap water is hard or alkaline, you may need to use reverse osmosis (RO) water or a mix of RO and tap water to achieve appropriate parameters. Peat filtration or the addition of botanicals can also help to lower pH and soften water naturally, though these methods require monitoring to ensure stability.

Filtration and Equipment

A good quality filter rated for the tank volume is essential. Blueberry Tetras do not require excessively powerful filtration, and in fact, they prefer gentle to moderate water flow. A hang-on-back filter, a small internal filter, or a canister filter with an adjustable flow rate or spray bar will all work well. If the outflow creates too much current, position it against the glass or use a lily pipe or spray bar to diffuse the flow.

Biological filtration capacity is the most important consideration. Ensure the filter media provides ample surface area for beneficial bacteria to colonise. Ceramic rings, bio-balls, or sintered glass media are all suitable. Avoid replacing all filter media at once, as this can cause a crash in the biological filter and a dangerous spike in ammonia or nitrite.

A reliable heater with an accurate thermostat is necessary to maintain the stable tropical temperatures this species requires. Submersible heaters are generally preferred, and it is wise to choose one appropriately sized for your tank volume. In larger tanks, two smaller heaters positioned at opposite ends can provide more even heat distribution.

Lighting should be moderate to subdued. While the specific lighting choice will partly depend on any live plants in the tank, the fish themselves prefer lower light levels. LED units with adjustable brightness or a dimmer are ideal, allowing you to find a balance that supports plant growth without overly illuminating the tank. Floating plants can be used to naturally reduce light intensity at the water surface.

An air pump is not strictly necessary if the filter provides adequate surface agitation for gas exchange, but a small air stone can be useful in warmer conditions when dissolved oxygen levels may drop. A tight-fitting lid or cover glass is also recommended, as tetras can be jumpers, particularly when startled or during spawning activity.

Diet and Feeding

The Blueberry Tetra is an omnivorous species with a diet that, in the wild, likely consists of small aquatic invertebrates, insect larvae, microcrustaceans, and organic detritus. In captivity, they are generally unfussy eaters that will accept a wide range of prepared and live foods.

A high-quality micro pellet or fine flake food should form the staple of their diet. Choose products formulated for small tropical fish, ideally with a good proportion of animal protein. Brands that include ingredients such as whole fish meal, insect larvae, or crustaceans tend to promote better colour and condition than those heavily based on plant fillers.

Supplementing the staple diet with live or frozen foods is highly recommended and will help to bring out the best colouration and encourage natural foraging behaviour. Suitable options include baby brine shrimp (Artemia nauplii), daphnia, cyclops, micro worms, grindal worms, and finely chopped bloodworm. Frozen foods are a convenient alternative to live cultures and are readily available from most aquarium retailers.

Feed small amounts two to three times daily rather than one large feeding. Blueberry Tetras have small stomachs and will benefit from frequent, modest meals. Each feeding should be consumed within two to three minutes; remove any uneaten food promptly to prevent it from fouling the water. Varying the diet across different food types throughout the week will ensure the fish receive a broad spectrum of nutrients and will keep them interested and active at feeding time.

Behaviour and Temperament

The Blueberry Tetra is a peaceful, shoaling species that spends the majority of its time in the mid-water column. In a well-maintained group, these fish will form a loose but cohesive shoal, drifting through the aquarium together and occasionally breaking apart to explore individually before regrouping. Their movement is graceful and unhurried, and they are a pleasure to observe as they navigate through plants and driftwood.

Within the group, mild hierarchical behaviour is normal. Males may display to one another with flared fins and intensified colour, jostling for position within the shoal. These interactions are typically harmless and rarely result in any physical damage, though they add dynamism and interest to the tank. Dominant males will often show the most vivid colouration, using their appearance to assert status.

Keeping Blueberry Tetras in groups of fewer than six is strongly discouraged. Insufficient group size can lead to stress, fin-nipping directed at other species, and a general failure to thrive. In small numbers, individual fish may become timid and reclusive, spending much of their time hiding rather than displaying their natural behaviour. A group of ten or more is ideal and will result in more confident, active, and colourful fish.

These tetras are not aggressive towards other species and will generally ignore tank mates that do not threaten them. They may be somewhat shy when first introduced to a new tank, particularly if the environment lacks sufficient cover, but they settle in relatively quickly once they feel secure. Avoid keeping them with boisterous, aggressive, or significantly larger fish, as this will cause chronic stress and may suppress their colouration and appetite.

Tank Mates

The Blueberry Tetra’s peaceful disposition makes it suitable for a well-planned community aquarium with other similarly sized, non-aggressive species. Ideal tank mates share a preference for soft, slightly acidic water and will not outcompete or intimidate the tetras. When choosing companions, consider species that occupy different levels of the water column to make the most of the available space and reduce any potential for territorial overlap.

Good tank mates

• Ember Tetra – A tiny, peaceful tetra that thrives in identical water conditions and adds a warm colour contrast to the blue of the Blueberry Tetra.
• Cardinal Tetra – Another soft water species with a calm temperament that coexists beautifully in a planted South American biotope.
• Rummy Nose Tetra – A tight-shoaling tetra that occupies a similar water column level and appreciates the same soft, acidic conditions.
• Pygmy Corydoras – A diminutive bottom-dwelling catfish that is entirely peaceful and helps to clean up uneaten food from the substrate.
• Salt and Pepper Corydoras – Another small Corydoras species that makes an excellent bottom-dwelling companion in a soft water setup.
• Otocinclus – A gentle algae-eating catfish that stays small and will not bother the tetras in any way.
• Chocolate Gourami – A soft water specialist that occupies the upper to mid-water column and is peaceful enough to share space with small tetras.
• Celestial Pearl Danio – A small, colourful species that does well in planted tanks and is compatible in temperament, though slightly cooler temperatures may be preferred.
• Amano Shrimp – Hardy, algae-eating invertebrates that are too large for the tetras to predate and contribute to tank cleanliness.
• Nerite Snail – Peaceful algae grazers that are entirely compatible and help to keep surfaces clean.

Fish to avoid

• Oscar – A large, predatory cichlid that would readily consume small tetras and requires entirely different tank conditions.
• Convict Cichlid – An aggressive cichlid, especially when breeding, that would bully and likely injure or kill Blueberry Tetras.
• Tiger Barb – A known fin-nipper with a boisterous temperament that would stress and harass small, peaceful tetras.
• Jack Dempsey – A large and territorial cichlid completely unsuitable for housing with small tetras.
• African Cichlids (Mbuna) – Require hard, alkaline water that is incompatible with the Blueberry Tetra’s needs, and most species are far too aggressive.
• Red Tail Catfish – A massive predatory catfish that would easily consume any small fish in the tank.
• Green Terror – An aggressive, territorial cichlid that poses a serious threat to any small, peaceful species.
• Betta (Siamese Fighting Fish) – While some community combinations can work, the Betta’s territorial nature and preference for still water can create conflicts, and Blueberry Tetras may nip at flowing fins.

Breeding

Breeding the Blueberry Tetra in captivity is achievable but requires some preparation and attention to water conditions. Like many Hyphessobrycon species, they are egg scatterers that show no parental care. Successful breeding is most likely in a dedicated breeding tank rather than a community setup, as eggs and fry are extremely vulnerable to predation, including from the parents themselves.

To condition breeding pairs or groups, feed a varied diet rich in live and frozen foods for several weeks prior to spawning attempts. Brine shrimp nauplii, daphnia, and micro worms are all excellent conditioning foods. Select healthy, well-coloured individuals for breeding; males that display the most vivid blue colouration and females that appear rounded in the abdomen are the best candidates.

The breeding tank should be small – around 20 to 30 litres is sufficient – and filled with soft, acidic water with a pH of approximately 5.5 to 6.0 and a temperature of 26 to 27 degrees Celsius. The tank should be dimly lit, as both eggs and fry are sensitive to bright light. A spawning mop or clumps of fine-leaved plants such as Java moss will provide a substrate for the eggs to fall into and will help to protect them from being eaten.

Spawning typically occurs in the early morning. The pair will engage in a courtship display, with the male flaring his fins and swimming alongside the female. Eggs are scattered among the plants or spawning mop and are adhesive to semi-adhesive in nature. Remove the adults immediately after spawning to prevent egg predation.

Eggs typically hatch within 24 to 36 hours, and the fry become free-swimming after a further three to four days. Initially, the fry are extremely small and will require infusoria or commercially available liquid fry food as their first food. After a week or so, they can graduate to freshly hatched brine shrimp nauplii. Growth is relatively slow, and it may take several months before the young fish begin to show their characteristic blue colouration. Maintain excellent water quality in the fry tank with gentle sponge filtration and frequent small water changes.

Common Diseases

The Blueberry Tetra is not particularly prone to any species-specific diseases, but like all freshwater fish, it is susceptible to the common ailments that affect aquarium species when water quality or husbandry standards slip.

Ich (white spot disease), caused by the protozoan parasite Ichthyophthirius multifiliis, is one of the most frequently encountered problems. It presents as small white spots on the body and fins, and affected fish may flash against hard surfaces or show increased respiratory rate. Ich is highly treatable with commercial white spot medications or by gradually raising the water temperature to 30 degrees Celsius over several days. However, given the Blueberry Tetra’s preference for soft, acidic water, some commercially available medications containing copper or malachite green should be used with caution and at reduced doses, as these compounds can be more toxic in soft water.

Fin rot, a bacterial infection typically triggered by poor water quality, can affect tetras that are kept in suboptimal conditions. Symptoms include fraying, discolouration, or erosion of the fins. Improving water quality through increased water changes is the first and most important step in treatment. In severe cases, antibacterial medications may be necessary.

Neon tetra disease (Pleistophora hyphessobryconis) is a microsporidian infection that can affect various tetra species. It causes progressive loss of colour, restlessness, and eventual wasting. There is no effective cure, and affected fish should be removed promptly to prevent spread to other individuals. Maintaining excellent water quality and quarantining new fish before adding them to an established tank are the best preventive measures.

Internal parasites can occasionally be a concern, particularly in wild-caught specimens. Signs may include weight loss despite a good appetite, white or stringy faeces, and lethargy. Anti-parasitic medications suitable for small freshwater fish can be used for treatment, and prophylactic treatment of newly acquired wild-caught fish is a sensible precaution.

Stress is perhaps the most significant risk factor for disease in Blueberry Tetras. Keeping them in appropriate group sizes, providing adequate cover, maintaining stable water parameters, and avoiding aggressive tank mates will go a long way towards preventing health problems before they arise.

FAQs

How many Blueberry Tetras should I keep together?

A minimum group of six is essential, but eight to twelve individuals is strongly recommended. Larger groups produce more natural shoaling behaviour, reduce stress on individual fish, and result in bolder, more colourful specimens. In groups that are too small, Blueberry Tetras tend to become shy, lose their colour intensity, and may redirect their social interactions towards other species in the form of fin-nipping.

Why are my Blueberry Tetras not showing their blue colour?

Subdued colouration is commonly seen in newly acquired specimens, stressed fish, or those kept in suboptimal conditions. Ensure the water parameters are within the recommended range, particularly that the water is soft and slightly acidic. A dark substrate, dim to moderate lighting, and the presence of tannin-releasing botanicals such as Indian almond leaves can significantly enhance colour. A high-quality diet rich in live and frozen foods will also help. It may take several weeks for newly introduced fish to settle in and display their full colouration.

Can Blueberry Tetras be kept with shrimp?

Adult Blueberry Tetras are generally safe to keep with larger shrimp species such as Amano shrimp and adult cherry shrimp. However, like most small tetras, they may predate on very small shrimplets if they encounter them. If you are hoping to breed shrimp in the same tank, provide dense plant cover such as Java moss to give the shrimplets hiding places. Keeping shrimp in a separate breeding tank and only introducing adults to the tetra tank is a more reliable approach if you want to maintain a shrimp colony.

Are Blueberry Tetras difficult to find in shops?

Yes, the Blueberry Tetra is considerably less common in the trade than species such as the neon tetra or cardinal tetra. They appear intermittently through specialist importers, online breeders, and occasionally at aquarium society auctions. If you are keen to acquire them, it is worth establishing contact with reputable specialist retailers or breeders who can notify you when stock becomes available. Be prepared to pay a premium compared to more commonly traded tetra species.

Do Blueberry Tetras need a heater?

Yes, a heater is necessary in the vast majority of home aquarium setups. Blueberry Tetras are tropical fish that require a stable temperature between 24 and 28 degrees Celsius. Most homes do not maintain ambient temperatures high or stable enough to meet this requirement year-round. A reliable submersible heater with an accurate thermostat is an essential piece of equipment for this species.

Related Guides

• Cardinal Tetra Care Guide – Another iconic soft water tetra from South America that pairs beautifully with Blueberry Tetras in a planted community tank.
• Ember Tetra Care Guide – A tiny, warm-toned tetra that complements the Blueberry Tetra’s blue colouration and shares similar care requirements.
• Green Neon Tetra Care Guide – A delicate, soft water tetra that thrives in the same blackwater-style setups favoured by Blueberry Tetras.
• Pygmy Corydoras Care Guide – An excellent bottom-dwelling companion for small tetra species, sharing a preference for soft, slightly acidic water.
• Otocinclus Care Guide – A peaceful algae-eating catfish that is one of the best choices for maintaining a clean planted tank alongside small tetras.