Black Heart Tetra

Quick Summary

The Black Heart Tetra is a peaceful, hardy shoaling fish that fits comfortably into most community aquariums. If you can keep a stable, well-planted tank and maintain a group of six or more, this understated little tetra will reward you with subtle beauty and engaging schooling behaviour.

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In this guide:

• Introduction
• Quick Stats
• Appearance
• Natural Habitat
• Tank Size and Setup
• Water Parameters
• Diet and Feeding
• Behaviour and Temperament
• Tank Mates
• Breeding

Introduction

The Black Heart Tetra (Hyphessobrycon copelandi) is a small, elegant characin originating from the river systems of northern South America. It was originally described in the genus Hyphessobrycon, but more recently (2024) has been moved into Megalamphodus, a currently valid genus that also includes species like the Bleeding Heart Tetra. Despite its somewhat confusing taxonomic history, the Black Heart Tetra remains a straightforward and rewarding species for community fishkeepers of all experience levels.

This species gets its common name from the distinctive dark, heart-shaped or wedge-shaped marking on its flanks, a feature it shares in spirit with its close relatives in the Hyphessobrycon group. It is not as widely available in the hobby as some of its cousins, but dedicated aquarists who seek it out are usually charmed by its calm demeanour, attractive finnage, and the way a well-settled shoal moves through a planted aquarium with quiet coordination.

In this guide we cover everything you need to keep Black Heart Tetras thriving: from water chemistry and tank dimensions to diet, breeding, and suitable companions. Whether you are planning a species-only biotope or integrating them into a mixed community, the information below will help you provide the best possible care.

Appearance

At first glance the Black Heart Tetra may appear understated compared to some of the more vividly coloured tetras, but closer inspection reveals a fish with real charm. The body is a classic tetra shape – laterally compressed and roughly diamond-profiled – reaching around 4 to 5 cm in total length when fully grown. The base colour is a soft silvery-olive to pale bronze, overlaid with a subtle iridescent sheen that catches the light as the fish changes direction.

The defining feature is the prominent dark blotch on the mid-flank, roughly behind the pectoral fin. This mark is variable in shape but often appears as a rounded or slightly elongated wedge, sometimes described as heart-shaped, which gives the fish its common name. In well-conditioned specimens the blotch is a deep, inky black and stands out sharply against the lighter body.

The fins are generally translucent to lightly tinted, with the dorsal fin sometimes showing a darker leading edge or a faint wash of black. Males in breeding condition may develop slightly longer dorsal and anal fin extensions, and their overall colouration tends to deepen. Females are usually a touch fuller-bodied, particularly when carrying eggs, and their colouration is marginally less intense. The eye is relatively large and often has a reddish-orange upper iris, a trait common across many Hyphessobrycon species, which adds a subtle but attractive detail when viewed at close range.

Juvenile fish are paler and the humeral blotch is less defined; as the fish matures and settles into a stable environment with good water quality, its colours and markings become progressively more vivid. Keeping this species over a dark substrate and among live plants brings out the best of its natural palette.

Natural Habitat

Hyphessobrycon copelandi is found across a wide area of northern South America, with records from tributaries and floodplain habitats within the Amazon and Orinoco river basins in Brazil, Venezuela, and parts of Guyana. It typically inhabits slow-moving or still waters such as forest streams, flooded forest margins, and backwater pools where the current is gentle and vegetation is abundant.

These environments are usually characterised by soft, acidic water stained a dark amber-brown by tannins leached from decomposing leaves and wood. The substrate is typically composed of fine sand or mud covered with a layer of leaf litter, fallen branches, and submerged roots. Overhead canopy cover reduces direct sunlight, creating a dimly lit, shaded habitat. Aquatic and marginal plants may be present, but the dominant structural features are woody debris and leaf beds rather than dense planted meadows.

Water chemistry in these habitats is typically soft and mildly acidic, with pH values often in the range of 5.5 to 6.5 and very low mineral hardness. Dissolved organic compounds from decaying vegetation give the water its characteristic tea-coloured tint and contribute to a rich micro-fauna of small invertebrates and insect larvae, which form the bulk of the tetra’s natural diet.

In the wild, Black Heart Tetras are found in mixed-species shoals alongside other small characins, pencilfish, and dwarf cichlids. Understanding this natural context is valuable for aquarium design: a tank that replicates the subdued lighting, soft water, and abundant cover of the fish’s native environment will produce the most natural behaviour and the best colouration.

Tank Size and Setup

A group of six Black Heart Tetras can be comfortably housed in a tank of at least 60 litres, though a larger aquarium of 80 to 100 litres or more is preferable if you intend to keep a bigger shoal or mix them with other species. As a general rule, aim for a group of at least six individuals; eight to twelve is better, as a larger shoal feels more secure and displays tighter, more natural schooling behaviour.

A rectangular tank with a decent front-to-back footprint is ideal. Black Heart Tetras are active mid-water swimmers, so horizontal swimming space matters more than height. Avoid very tall, narrow tanks that offer limited lateral movement.

For the substrate, fine sand or smooth gravel in a dark colour works well. Dark substrates help the fish feel secure and bring out the contrast of their markings. A layer of dried leaf litter – Indian almond leaves or oak leaves – scattered over the substrate is an excellent addition, both aesthetically and functionally. The leaves release tannins that gently soften and acidify the water, mimicking the blackwater conditions these fish encounter in the wild, and they also support the growth of biofilm and microorganisms that supplement the diet.

Planting the tank generously is highly recommended. Dense clusters of stem plants such as Cabomba, Vallisneria, or Hygrophila along the back and sides provide cover and break lines of sight, while floating plants like Amazon Frogbit or Salvinia diffuse overhead light. This species appreciates subdued lighting, so a moderate to low light level is ideal. If you are running a high-output planted light, floating plants will help to create shaded areas the tetras can retreat to.

Driftwood and bogwood pieces add further structure and visual interest while also leaching tannins. Arrange hardscape and plants to create open swimming areas in the centre and front of the tank, with denser planting and cover towards the rear and sides. This layout gives the shoal room to move freely while still providing the sheltered zones they prefer for resting.

A secure, well-fitted lid is essential. Like many small tetras, Black Heart Tetras can and will jump, particularly when startled or during the initial settling-in period. A tight-fitting cover glass or lid prevents losses.

Water Parameters

Black Heart Tetras are adaptable within a fairly broad range of water chemistry, which is one of the reasons they are considered an easy species for beginners. That said, they will look and behave their best in soft, slightly acidic to neutral water that approximates their natural habitat. Stability is more important than hitting a precise number; sudden swings in pH or temperature are far more harmful than keeping the fish at the slightly harder end of their tolerance range.

Perform regular partial water changes of around 20 to 30 per cent weekly to keep nitrate levels low and maintain overall water quality. When topping up or performing water changes, always match the temperature of the new water closely to the tank temperature to avoid thermal shock. If your tap water is significantly harder or more alkaline than the ideal range, consider blending it with reverse-osmosis (RO) water to bring hardness and pH down to more suitable levels.

The use of natural tannin sources such as Indian almond leaves, alder cones, or driftwood can help to gently lower pH and soften the water over time, while also providing the amber-tinted conditions in which these tetras look most striking. Peat filtration is another option, though it requires monitoring to avoid excessive pH drops.

Filtration and Equipment

Filtration should provide reliable biological, mechanical, and chemical filtration while avoiding excessively strong currents. Black Heart Tetras come from slow-moving or still waters and do not appreciate being buffeted by powerful flow. A hang-on-back filter, a small canister filter, or a sponge filter rated for the tank volume will all work well. If using a filter with an adjustable flow rate, dial it back so that the surface of the water ripples gently without creating a strong current across the tank.

Sponge filters are particularly well-suited if you plan to breed these fish, as they provide gentle filtration without any risk of fry being sucked into the intake. In a standard community setup, a hang-on-back or small external canister filter offers the convenience of easy media access and typically includes space for chemical media such as activated carbon if needed.

An aquarium heater is necessary to maintain a stable tropical temperature within the 23 to 28 C range. Choose a heater rated appropriately for your tank volume – generally around 1 watt per litre as a rough guide. A reliable, adjustable heater with a built-in thermostat is worth the investment, as temperature stability is critical for the long-term health of any tropical fish.

Lighting should be moderate to subdued. If you are growing live plants that require higher light, balance this with floating plants or shaded areas. LED fixtures with adjustable intensity or a timer set to provide a photoperiod of 8 to 10 hours per day are ideal. Avoid leaving the lights on for extended periods, as this encourages algae growth and can stress the fish.

A thermometer – either a digital probe or a simple glass stick-on type – should be visible at all times so you can quickly spot any heater malfunction. Testing kits for ammonia, nitrite, nitrate, and pH are essential tools for ongoing water quality monitoring.

Diet and Feeding

Black Heart Tetras are omnivorous and unfussy feeders, which makes them very straightforward to cater for. In the wild, their diet consists mainly of small invertebrates, insect larvae, micro-crustaceans, and organic detritus. In the aquarium they readily accept a wide variety of foods.

A high-quality micro-pellet or flake food designed for small tropical fish should form the staple of their diet. Look for products with whole fish or insect meal listed high in the ingredients and minimal fillers. Supplement this base diet regularly with frozen or live foods such as daphnia, baby brine shrimp (Artemia nauplii), cyclops, mosquito larvae, and micro-worms. These protein-rich foods help to maintain condition, enhance colouration, and are particularly important if you are conditioning the fish for breeding.

Freeze-dried foods like bloodworm and tubifex are accepted but should be offered sparingly, as they can cause digestive issues if fed in large quantities or if they swell inside the fish’s gut. Always soak freeze-dried items briefly before feeding to reduce this risk.

Feed small amounts once or twice daily – only as much as the fish can consume within two to three minutes. Overfeeding is one of the most common mistakes in fishkeeping and leads to deteriorating water quality, which in turn causes stress and disease. In a well-planted tank with leaf litter and biofilm, the tetras will also graze on microorganisms between meals, supplementing their diet naturally.

Varying the diet across the week keeps the fish interested and ensures a broad nutritional profile. A simple rotation might be: flake or pellet on most days, frozen daphnia or brine shrimp two or three times a week, and a fast day once a week to allow the digestive system to clear.

Behaviour and Temperament

The Black Heart Tetra is a peaceful, sociable fish that thrives in the company of its own kind. It is a classic shoaling species: in the wild it lives in groups that can number in the dozens or hundreds, and in the aquarium it relies on the presence of conspecifics to feel secure. A solitary Black Heart Tetra, or one kept in an inadequately small group, will often become stressed, skittish, and may hide constantly or refuse food.

Always keep this species in groups of at least six, ideally more. In a shoal of eight to twelve or above, the fish display far more natural, relaxed behaviour. You will see the group cruising the mid-water zone together, occasionally breaking formation to investigate food or interact briefly before regrouping. Males may engage in minor sparring or fin-flaring displays amongst themselves, but these interactions are harmless and do not result in injury.

Within the aquarium hierarchy, Black Heart Tetras are firmly in the peaceful camp. They do not nip fins, harass other species, or compete aggressively for food. They occupy the middle layer of the water column for the most part, occasionally venturing to the surface to feed or dipping lower to investigate the substrate and leaf litter.

They can be somewhat timid, especially in sparsely decorated tanks or when first introduced to a new environment. Providing ample plant cover, dim lighting, and a dark substrate will help them settle in more quickly. Once established and comfortable, they become bolder and spend more time in the open, showing off their natural behaviour and colouration.

Black Heart Tetras are not particularly active or boisterous by tetra standards; they have a calm, measured swimming style compared to, say, Buenos Aires Tetras or Serpae Tetras. This makes them excellent companions for other peaceful, non-aggressive species, including sensitive fish like dwarf cichlids and shy catfish.

Tank Mates

Selecting suitable tank mates for the Black Heart Tetra is straightforward, as this species is compatible with a wide range of peaceful community fish. The key considerations are that companions should be non-aggressive, of a similar size, and should not be so boisterous or fast-feeding that the tetras are out-competed for food. Avoid anything large enough to view the tetra as a meal, and steer clear of known fin-nippers or territorial aggressors.

Good tank mates

• Neon Tetra – A similarly sized, peaceful shoaling tetra that occupies the same water column without competition.
• Cardinal Tetra – Another soft-water-loving tetra that shares the same habitat preferences and gentle temperament.
• Ember Tetra – A tiny, calm species that adds warm colour and coexists peacefully in planted setups.
• Rummy-nose Tetra – An excellent mid-water shoaling companion with complementary behaviour.
• Panda Corydoras – A peaceful bottom-dweller that stays out of the tetra’s way and helps keep the substrate clean.
• Pygmy Corydoras – A diminutive, non-competitive catfish ideal for smaller community tanks.
• Otocinclus – A gentle algae-eating catfish that poses no threat and appreciates similar water conditions.
• Apistogramma cacatuoides – A dwarf cichlid that pairs well in a well-planted tank, provided there is enough space and cover.
• Harlequin Rasbora – A calm, similarly sized shoaling fish that thrives in soft, slightly acidic water.
• Amano Shrimp – A useful clean-up crew member that is too large for the tetras to bother.

Fish to avoid

• Oscar – Far too large and predatory; would view Black Heart Tetras as food.
• Red-bellied Piranha – An aggressive predator completely incompatible with small tetras.
• Convict Cichlid – Territorial and aggressive, especially when breeding, and will harass or kill small tetras.
• Tiger Barb – A known fin-nipper that can stress and damage peaceful tetras, particularly those with longer finnage.
• Serpae Tetra – Despite being a related tetra, Serpae Tetras can be nippy and may bully quieter species.
• Jack Dempsey – A large, territorial cichlid that poses a serious threat to any small, peaceful fish.
• African Jewel Cichlid – Highly territorial and aggressive, completely unsuitable for a peaceful tetra community.

Breeding

Breeding Black Heart Tetras is achievable in the home aquarium but requires some preparation and attention to water conditions. Like most small characins, they are egg-scatterers and provide no parental care. The adults will readily consume their own eggs and fry if given the opportunity, so a dedicated breeding setup is strongly recommended.

Begin by selecting a well-conditioned pair or a small group (two males to three or four females works well). Condition the breeding group for one to two weeks on a diet rich in live and frozen foods – baby brine shrimp, daphnia, and micro-worms are ideal. This high-protein diet helps females develop eggs and brings both sexes into peak breeding condition.

Set up a separate breeding tank of around 20 to 30 litres. The water should be soft and acidic – a pH of 5.5 to 6.5 and a GH of 2 to 4 dGH is ideal. Temperature should be at the warmer end of the species’ range, around 26 to 28 C. Use aged, tannin-stained water if possible; adding Indian almond leaves or peat extract can help achieve this. Filtration should be gentle – an air-driven sponge filter is perfect.

The bottom of the breeding tank should contain a spawning medium that allows eggs to fall out of reach of the adults. A layer of glass marbles, a mesh spawning grate raised slightly off the bottom, or dense clumps of fine-leaved plants like Java Moss or spawning mops all serve this purpose. Keep lighting dim or cover the sides of the tank to reduce disturbance.

Introduce the conditioned fish to the breeding tank in the evening. Spawning typically occurs in the early morning hours. The male will court the female with fin displays and side-by-side swimming, and the pair will scatter adhesive or semi-adhesive eggs among the plants or over the substrate. A single spawning can produce anywhere from 50 to over 200 eggs, depending on the size and condition of the female.

Remove the adults immediately after spawning to prevent egg predation. The eggs are small and translucent and will hatch in approximately 24 to 36 hours at 27 C. The fry are initially tiny and will absorb their yolk sacs over the following two to three days. Once free-swimming, they can be fed infusoria or liquid fry food for the first week, graduating to freshly hatched brine shrimp nauplii and microworms as they grow.

Growth is steady but not rapid. Maintain excellent water quality in the fry tank with small, frequent water changes using water of matched temperature and chemistry. The fry are sensitive to water quality fluctuations, so stability is paramount. After four to six weeks, the juveniles will be large enough to accept finely crushed flake food and can gradually be transitioned to the diet of the adults.

Common Diseases

Black Heart Tetras are generally hardy and not especially prone to disease when kept in clean, stable water with a balanced diet. However, like all freshwater fish, they can fall victim to a range of common ailments if conditions deteriorate or stress compromises their immune system.

Ichthyophthirius multifiliis, commonly known as white spot disease or ich, is perhaps the most frequently encountered illness in tropical aquaria. It presents as small white cysts on the body and fins, and affected fish often flash (rub against surfaces) and show signs of irritation. Ich is typically triggered by temperature drops or stress from poor water quality. Treatment involves gradually raising the water temperature to 28 to 30 C and adding an appropriate ich medication to the tank. Caught early, ich is very treatable.

Fin rot is another common issue, usually caused by bacterial infection following fin damage or chronic exposure to poor water quality. Symptoms include frayed, discoloured, or receding fin edges. Improving water quality through increased water changes is often sufficient to halt mild cases; more advanced infections may require treatment with an antibacterial medication.

Fungal infections can appear as white, cotton-like growths on the body or fins, often developing on existing wounds or areas weakened by other infections. Anti-fungal treatments are widely available and effective when used promptly.

Internal parasites can occasionally affect wild-caught specimens. Signs include weight loss despite normal appetite, white or stringy faeces, and lethargy. Anti-parasitic foods or dedicated internal parasite treatments can address these issues.

Neon Tetra Disease (Pleistophora hyphessobryconis), despite its name, can affect various tetra species, including Hyphessobrycon. It is caused by a microsporidian parasite and presents as pale, discoloured patches on the body, loss of colour, erratic swimming, and progressive wasting. Unfortunately, there is no reliable cure; affected fish should be removed promptly to prevent the spread of spores to tank mates.

Prevention is always better than cure. Maintain stable water parameters, avoid overstocking, quarantine new arrivals for at least two weeks before adding them to an established tank, and provide a varied, nutritious diet. These simple measures dramatically reduce the likelihood of disease outbreaks.

FAQs

How many Black Heart Tetras should I keep together?

A minimum group of six is essential, but eight to twelve or more is strongly recommended. Larger groups produce more natural shoaling behaviour, reduce individual stress, and allow the fish to display their best colouration. In a group that is too small, individuals tend to be nervous, hide frequently, and may lose colour.

Can Black Heart Tetras live with shrimp?

Yes, they can coexist with larger shrimp species such as Amano Shrimp and adult Cherry Shrimp. However, very small shrimp and shrimplets (baby shrimp) may be at risk of predation. If you are trying to breed dwarf shrimp, dense plant cover and moss will give the young shrimp a better chance of survival, but some losses are likely in a tank shared with any tetra species.

Are Black Heart Tetras fin-nippers?

No, Black Heart Tetras are not known for fin-nipping behaviour. They are one of the more peaceful tetra species and generally leave the fins of other fish alone. They are safe to keep alongside long-finned or slow-moving species, though pairing them with extremely slow fish like fancy guppies still requires observation to be safe.

Do Black Heart Tetras need a heater?

Yes, unless you live in a consistently warm climate where room temperature never drops below 23 C. These are tropical fish that require a stable temperature within the 23 to 28 C range. An adjustable aquarium heater with a thermostat is the most reliable way to achieve this.

What is the difference between a Black Heart Tetra and a Bleeding Heart Tetra?

The Bleeding Heart Tetra (Hyphessobrycon erythrostigma) is a larger, deeper-bodied relative that can reach 6 to 7 cm and displays a vivid red or pink spot on the flank rather than a dark black blotch. While both species share a similar body shape and belong to the same genus, the Black Heart Tetra (H. copelandi) is smaller, more subtly coloured, and has the characteristic dark marking that gives it its common name. Care requirements are broadly similar, but the Bleeding Heart Tetra generally needs a slightly larger tank due to its bigger adult size.

Related Guides

• Bleeding Heart Tetra Care Guide – A close relative with similar care needs but a larger adult size and distinctive red flank spot.
• Cardinal Tetra Care Guide – Another popular soft-water tetra that makes an excellent companion in a blackwater-style community.
• Ember Tetra Care Guide – A tiny, peaceful tetra ideal for nano and planted community setups alongside Black Heart Tetras.
• Apistogramma cacatuoides Care Guide – A dwarf cichlid that pairs beautifully with small tetras in a well-planted South American biotope.
• Panda Corydoras Care Guide – A peaceful bottom-dwelling catfish that complements tetra communities perfectly.