Bleeding Heart Tetra

Quick summary

The Bleeding Heart Tetra is an easy-to-keep, peaceful schooling fish that suits beginners with at least a 110 litre tank, provided it’s kept in groups of six or more to stay confident and avoid fin-nipping. It’s adaptable to a range of water conditions, though breeding this species is considered difficult and best left to more experienced keepers.

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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 Bleeding Heart Tetra (Megalamphodus erythrostigma, though now frequently placed under Hyphessobrycon erythrostigma) is one of the most visually striking members of the tetra family available to freshwater aquarists. Named for the vivid blood-red spot on each flank – resembling a drop of blood or a small heart – this South American species has been a firm favourite in the hobby since its introduction in the mid-twentieth century. It combines elegant finnage, subtle iridescent colouration, and a peaceful but characterful temperament, making it an excellent centrepiece schooling fish for community aquariums.

Native to the upper Amazon basin, particularly the tributaries and slow-moving waterways of Colombia and Peru, the Bleeding Heart Tetra inhabits soft, acidic waters shaded by dense forest canopy. In the aquarium it thrives when these conditions are at least partially replicated, though captive-bred specimens have proven adaptable to a broader range of water chemistry. Adults reach a respectable size for a tetra, typically around 6 to 7 centimetres, and they can live for five years or more with attentive care. Their slightly deeper body profile, long flowing fins (especially in mature males), and that unmistakable scarlet blotch ensure they stand out even among a diverse community of tropical fish.

This guide covers everything you need to know to keep Bleeding Heart Tetras healthy and content, from tank setup and water parameters to diet, breeding, compatible tank mates, and common health concerns. Whether you are a newcomer considering your first school of tetras or an experienced aquarist looking to add a splash of colour to an existing community, the Bleeding Heart Tetra is a rewarding species well worth your attention.

Appearance

The Bleeding Heart Tetra possesses a deep, laterally compressed body that is noticeably taller in proportion than many of the slimmer tetra species. This gives the fish a somewhat robust, disc-like profile when viewed from the side. The base body colour is a warm pinkish-silver that can shift through soft lavender and beige tones depending on lighting, mood, and water conditions. A subtle iridescent sheen covers much of the flank, catching the light attractively as the fish moves through the water column.

The defining feature is, of course, the striking blood-red to deep crimson spot located roughly midway along the flank, just behind the pectoral fin and slightly below the lateral line. This marking is present in both sexes and is visible from a young age, though it becomes more vivid and well-defined as the fish matures. The intensity of this spot can fluctuate; fish in peak health and kept in soft, slightly acidic water with subdued lighting tend to display the most saturated colour.

The fins are another highlight of this species. The dorsal fin is tall and may carry black and white markings, with mature males developing noticeably elongated dorsal and anal fins that trail elegantly behind the body. The anal fin is long-based and often edged in black or dark grey. The caudal fin is forked and translucent with occasional pinkish or reddish tinting. Females tend to have shorter, more rounded fins overall, and their bodies are generally slightly plumper, especially when gravid.

Juvenile Bleeding Heart Tetras are somewhat paler and less distinctly marked than adults, but the red flank spot is usually visible even in young fish of around 2 centimetres. As they grow, the iridescence and fin extensions develop, and well-kept specimens become increasingly impressive. Dominant males in a large school may display particularly vivid colouration and exaggerated finnage as they compete for status within the group hierarchy.

Natural Habitat

Bleeding Heart Tetras originate from the upper Amazon basin, with the majority of wild populations found in Colombia and Peru. They inhabit slow-moving tributaries, forest streams, and floodplain lakes where the water is typically stained a dark tea colour by decomposing organic matter such as fallen leaves, branches, and other plant debris. These blackwater and clearwater environments are characterised by soft, acidic water with minimal mineral content.

The forest canopy above these waterways provides heavy shade, so Bleeding Heart Tetras are accustomed to relatively low light levels. The substrate in their natural habitats is usually composed of fine sand, leaf litter, and submerged wood, creating a complex environment rich in hiding places and foraging opportunities. Aquatic and marginal vegetation is present but often not dense, as the low light beneath the canopy limits plant growth.

Water temperatures in their native range typically sit between 24 and 28 degrees Celsius, with pH values often falling between 5.0 and 6.5 and very low general hardness. The fish are found in schools, often alongside other small characins, and they occupy the middle water column, darting between patches of submerged wood and leaf litter to feed on small invertebrates, insect larvae, and organic detritus.

Understanding this natural environment is valuable for aquarists. While captive-bred Bleeding Heart Tetras are adaptable, replicating elements of their wild habitat – soft, slightly acidic water, subdued lighting, driftwood, and leaf litter – will bring out the best colouration and encourage the most natural behaviours. A biotope-style setup inspired by an Amazonian forest stream is an ideal way to showcase this species.

Tank Size and Setup

A minimum tank size of 110 litres is recommended for a school of Bleeding Heart Tetras. These are active, moderately sized tetras that need room to swim and establish a natural social hierarchy. A tank with a footprint of at least 80 centimetres in length is preferable, as horizontal swimming space is more important than height for this species. If you plan to keep a larger school of ten or more, or wish to house them in a community alongside other species, a tank of 150 litres or more would be a better choice.

When setting up the aquarium, aim to replicate the feel of a shaded Amazonian stream. A sandy substrate in natural tones – beige, brown, or dark grey – works well and provides a good contrast to the fish’s colouration. Add pieces of driftwood and bogwood to create structure, hiding spots, and visual barriers. These elements also leach tannins into the water, gently acidifying it and creating the slight amber tint that mimics blackwater conditions. Dried Indian almond leaves (Terminalia catappa) or oak leaves scattered on the substrate serve a similar purpose and add a naturalistic touch.

Live plants are appreciated and help to diffuse light, provide cover, and improve water quality. Choose species tolerant of lower light levels and soft water, such as Java fern (Microsorum pteropus), Anubias species, Cryptocoryne species, and floating plants like Amazon frogbit (Limnobium laevigatum). Floating plants are particularly beneficial as they dim the lighting and make the tetras feel more secure, which in turn encourages bolder behaviour and better colour display.

Avoid overly bright lighting, as Bleeding Heart Tetras tend to look washed out and behave more timidly under intense illumination. If your tank is brightly lit for plant growth, ensure there are shaded areas provided by floating plants or tall stem plants. A dark background on the rear glass can also help to showcase the fish’s colours effectively.

A secure lid or cover glass is advisable. Tetras can be skittish, and Bleeding Heart Tetras are capable of jumping, particularly when startled or during the initial settling-in period. Ensuring the tank is well covered reduces the risk of losses from jumping.

Water Parameters

Bleeding Heart Tetras are adaptable fish, particularly when captive-bred, but they look and behave at their best when kept in soft, slightly acidic to neutral water. Stability is more important than hitting exact numbers, so aim to maintain consistent parameters and avoid sudden swings in temperature, pH, or hardness.

A temperature of around 25 to 26 degrees Celsius is ideal for most community setups. If you are keeping wild-caught specimens, aim for the softer, more acidic end of the range (pH 5.5-6.5, GH 2-6 dGH) for the best results. Captive-bred fish generally tolerate slightly harder, more neutral water without issue, though very hard or alkaline conditions should be avoided as these can cause stress over time.

Regular water changes of 20-30% per week are essential to keep nitrate levels low and maintain water quality. Bleeding Heart Tetras are not exceptionally sensitive, but consistently poor water quality will lead to faded colours, stress-related illness, and a shortened lifespan. Test your water regularly using a reliable liquid test kit, paying particular attention to ammonia, nitrite, and nitrate readings.

Filtration and Equipment

A good quality filter rated for the volume of your tank is essential. Bleeding Heart Tetras come from slow-moving to moderately flowing waters, so avoid creating excessively strong currents in the aquarium. A hang-on-back filter, internal canister, or external canister filter all work well, provided the output can be adjusted or diffused to prevent overly turbulent flow. Positioning the filter outlet against the rear glass or using a spray bar can help to distribute flow gently across the tank.

Biological filtration capacity is the priority. Choose a filter with ample space for biological media such as ceramic rings, sintered glass, or foam. This ensures the nitrogen cycle operates efficiently, converting ammonia and nitrite to the less harmful nitrate. Supplementary mechanical filtration using fine filter floss or sponge will help to keep the water clear, and chemical media such as activated carbon can be used periodically if needed, though it is not essential for day-to-day operation.

A reliable aquarium heater with a thermostat is necessary to maintain stable tropical temperatures. Choose a heater appropriately sized for your tank volume – as a general rule, allow approximately 1 watt per litre. In larger tanks or in rooms subject to temperature fluctuations, two smaller heaters can be used for redundancy and more even heat distribution.

Lighting should be moderate to subdued. LED fixtures with adjustable intensity are ideal, as they allow you to tailor the brightness to suit both the fish and any live plants. If using a fixed-output light, floating plants can be used to reduce the intensity reaching the lower levels of the tank. A timer set to provide 8-10 hours of light per day will establish a natural photoperiod.

An air pump is not strictly necessary if your filter provides adequate surface agitation for gas exchange, but a gentle airstone can be a useful addition, particularly in warmer weather when dissolved oxygen levels may drop. Avoid vigorous aeration that creates excessive surface turbulence, as this is not characteristic of the species’ natural environment.

Diet and Feeding

Bleeding Heart Tetras are omnivorous and unfussy feeders in the aquarium, accepting a wide range of prepared, frozen, and live foods. A varied diet is the key to keeping them in optimal health and colour. Offer a high-quality flake or micro-pellet food as the staple, choosing products formulated for tropical community fish or specifically for characins.

Supplement the staple diet with regular offerings of frozen or live foods. Bloodworm, brine shrimp (Artemia), daphnia, mosquito larvae, and cyclops are all readily accepted and provide valuable protein and nutrients that enhance colour and condition. Frozen foods are convenient and widely available; thaw a small portion in a little tank water before feeding to avoid introducing ice directly into the aquarium.

Vegetable matter should also form part of the diet. Blanched spinach, spirulina-based flakes or wafers, and crushed peas can be offered occasionally. Some high-quality flake and pellet foods already contain plant-based ingredients, which may be sufficient if you feed a good brand.

Feed small amounts two to three times per day rather than one large feeding. Bleeding Heart Tetras have relatively small stomachs, and overfeeding leads to uneaten food fouling the water. Each feeding should be consumed within two to three minutes. Remove any uneaten food promptly to maintain water quality.

Avoid relying solely on a single food type. Dietary variety promotes a strong immune system, vibrant colouration, and overall vitality. Fish kept on a monotonous diet of basic flake alone often appear pale and may be more susceptible to illness. The occasional treat of live food, in particular, can trigger natural hunting behaviours and keep the fish active and engaged.

Behaviour and Temperament

Bleeding Heart Tetras are generally peaceful, sociable fish that do best when kept in groups. They are a schooling species and should be maintained in groups of at least six individuals, though eight to twelve is preferable. In smaller groups or when kept singly, they often become stressed, timid, and prone to fin-nipping or other behavioural issues.

Within the school, a subtle but fascinating social hierarchy develops. Males will frequently display to one another, flaring their elongated dorsal and anal fins in ritualised posturing. These interactions are usually harmless and entertaining to observe, though occasionally a particularly dominant male may chase subordinates. Providing adequate space and visual barriers in the form of plants and driftwood ensures that less dominant individuals can retreat if needed.

In terms of activity level, Bleeding Heart Tetras occupy the middle water column for the most part, cruising through open swimming areas and weaving between decor. They are not as hyperactive as some smaller tetras but are far from sedentary, maintaining a steady, graceful movement throughout the day. They tend to be most active during feeding times and may become somewhat more subdued under bright lighting or in sparsely decorated tanks.

One notable trait is that Bleeding Heart Tetras can be mildly nippy towards long-finned tank mates, particularly if kept in insufficient numbers. This tendency is greatly reduced in larger schools, where the fish direct their social interactions towards one another rather than towards other species. Choosing tank mates carefully and maintaining a proper school size will minimise any fin-nipping issues.

They are not particularly shy once settled, and a well-established school in a suitably set up tank will spend most of its time in the open, making them an excellent display species. New additions may hide for the first few days but typically gain confidence quickly, especially if there are already established fish in the tank.

Tank Mates

Bleeding Heart Tetras are well suited to community aquariums alongside other peaceful, similarly sized species. Their calm disposition and preference for the middle water column mean they rarely come into conflict with bottom-dwellers or surface-dwelling fish. The key considerations when choosing tank mates are to avoid very small species that might be intimidated, very long-finned species that might be nipped, and aggressive or territorial fish that could harass the tetras. Aim for species that share similar water parameter preferences – soft to moderately hard, slightly acidic to neutral water at tropical temperatures.

Good tank mates

• Rummy Nose Tetra – A peaceful, similarly sized tetra that thrives in the same soft, warm water conditions and makes a visually striking companion school.
• Cardinal Tetra – A classic Amazonian species that occupies the lower-middle water column and complements Bleeding Heart Tetras beautifully without competition.
• Corydoras sterbai – A hardy, heat-tolerant bottom-dwelling catfish that peacefully scavenges the substrate and adds activity to lower tank levels.
• Bristlenose Pleco – A peaceful algae-eating catfish that stays out of the tetras’ way and helps to keep tank surfaces clean.
• Kuhli Loach – A gentle, nocturnal bottom-dweller that coexists happily with mid-water schooling fish and adds interest to the lower tank.
• Pearl Gourami – A calm, elegant surface-to-mid-water species that tolerates the same water parameters and rarely causes conflict.
• Harlequin Rasbora – A peaceful schooling fish of similar size that enjoys soft, acidic water and adds complementary colour to the tank.
• Apistogramma cacatuoides – A small, relatively peaceful dwarf cichlid that occupies the lower levels and coexists well in a suitably sized tank.
• Otocinclus – A tiny, peaceful algae grazer that stays on surfaces and plants, posing no threat to or from the tetras.

Fish to avoid

• Oscar – A large, predatory cichlid that would view Bleeding Heart Tetras as food and requires completely different tank conditions.
• Betta – The long, flowing fins of male bettas make them prime targets for nipping, and bettas may also be stressed by active schooling fish.
• Tiger Barb – A notorious fin-nipper that can harass the relatively slow-moving Bleeding Heart Tetras and cause stress.
• Jack Dempsey – An aggressive, territorial cichlid far too large and belligerent to house with peaceful tetras.
• Green Terror – A highly aggressive South American cichlid that would dominate and likely injure or kill smaller tank mates.
• Red Tail Catfish – A massive predatory catfish entirely unsuitable for community tanks, capable of swallowing tetras whole.
• African Cichlids (Mbuna) – Require hard, alkaline water and are highly territorial, making them completely incompatible in both temperament and water chemistry.
• Flowerhorn – An extremely aggressive hybrid cichlid that should be kept alone and would quickly kill any tetra placed in its tank.

Breeding

Breeding Bleeding Heart Tetras in captivity is achievable but considered difficult, requiring specific water conditions and careful preparation. They are egg-scattering spawners that show no parental care, and the eggs and fry are highly sensitive to light and water quality. Successful breeding is most likely in a dedicated breeding tank rather than in a community setup.

To condition a breeding pair or group, feed heavily with high-quality live and frozen foods such as bloodworm, brine shrimp, and daphnia for two to three weeks prior to spawning attempts. Select the healthiest, most vibrantly coloured individuals – males can be identified by their longer, more pointed dorsal and anal fins, while females are generally plumper and have shorter, more rounded fins.

Set up a separate breeding tank of around 40 to 60 litres with very soft, acidic water – aim for a pH of 5.5 to 6.0, a GH of 1 to 4 dGH, and a temperature of 26 to 28 degrees Celsius. Use an air-driven sponge filter to provide gentle filtration without risking the intake of eggs or fry. The tank should be dimly lit or kept in near-darkness, as the eggs are highly sensitive to light. A layer of fine-leaved plants such as Java moss, or a mesh spawning grid positioned above the substrate, will help to protect eggs from being eaten by the parents.

Introduce the conditioned pair or a small group to the breeding tank in the evening. Spawning, if it occurs, typically takes place in the early morning. The female scatters eggs among plants or over the substrate, and the male fertilises them externally. The eggs are small, translucent, and adhesive, sticking to plant surfaces and decor. After spawning, remove the adults promptly to prevent egg predation.

The eggs hatch in approximately 24 to 36 hours, and the fry become free-swimming after a further three to four days. Keep the breeding tank very dimly lit during this period, as bright light can kill the eggs and young fry. Initial food should be infusoria or commercially available liquid fry food, transitioning to newly hatched brine shrimp (Artemia nauplii) once the fry are large enough to accept them. Growth can be slow, and the fry require consistently clean water and frequent small feedings to develop successfully.

Breeding success rates can be improved by using rainwater or RO (reverse osmosis) water to achieve the necessary softness, and by adding tannin sources such as Indian almond leaves or alder cones to the breeding tank. Patience is key, as even experienced breeders may need multiple attempts before achieving a successful spawn.

Common Diseases

Bleeding Heart Tetras are reasonably hardy fish when kept in appropriate conditions, but like all aquarium species, they are susceptible to a range of common freshwater diseases. The best defence against illness is prevention through good husbandry – maintaining stable water parameters, performing regular water changes, feeding a varied diet, and avoiding overstocking.

Ich (white spot disease), caused by the protozoan parasite Ichthyophthirius multifiliis, is one of the most frequently encountered illnesses. It manifests as small white spots on the body, fins, and gills, often accompanied by flashing (rubbing against surfaces) and lethargy. Ich is highly contagious and should be treated promptly by raising the water temperature to 28-30 degrees Celsius and administering a proprietary ich treatment according to the manufacturer’s instructions. Bleeding Heart Tetras generally tolerate standard ich treatments well, but always check that any medication is safe for use with tetras and other scaleless or sensitive species in the tank.

Fin rot is another common condition, typically caused by bacterial infection secondary to poor water quality, stress, or fin damage from nipping. Affected fins appear ragged, frayed, or discoloured, and the condition can progress to the body if left untreated. Improving water quality through increased water changes is often the first and most effective step. In more advanced cases, antibacterial treatments may be necessary.

Columnaris (cotton wool disease) is a bacterial infection that causes white or greyish cotton-like patches on the body, fins, and mouth. It can spread rapidly and is often associated with stress or poor water quality. Treatment involves antibacterial medications and improvement of environmental conditions.

Internal parasites can occasionally affect Bleeding Heart Tetras, particularly wild-caught specimens. Symptoms may include weight loss despite a healthy appetite, white or stringy faeces, and a generally emaciated appearance. Anti-parasitic foods or medications designed for internal parasites can be used to treat affected fish.

Neon tetra disease (Pleistophora hyphessobryconis), despite its name, can affect a range of characin species including Bleeding Heart Tetras. It is caused by a microsporidian parasite and is characterised by loss of colour, cysts in the muscle tissue, difficulty swimming, and wasting. Unfortunately, there is no effective treatment, and affected fish should be humanely euthanised and removed to prevent transmission to other tank inhabitants.

Quarantining all new fish for two to four weeks before adding them to an established tank is a valuable practice that can prevent the introduction of disease. Observe new arrivals carefully during this period for any signs of illness before allowing them to join the main display.

FAQs

How many Bleeding Heart Tetras should I keep together?

A minimum of six is recommended, but a group of eight to twelve is ideal. Larger schools result in more natural behaviour, reduced stress, and less likelihood of fin-nipping towards other species. In small groups, individual fish may become timid, withdrawn, or aggressive, so always aim for the largest school your tank can comfortably support.

Can Bleeding Heart Tetras live in hard water?

Captive-bred Bleeding Heart Tetras can tolerate moderately hard water (up to around 12 dGH), but they will display their best colours and most natural behaviour in softer, slightly acidic conditions. Very hard or highly alkaline water should be avoided as it can cause long-term stress and health issues. If your tap water is hard, consider blending it with RO water to bring the hardness down to a more suitable level.

Are Bleeding Heart Tetras fin nippers?

They can be mildly nippy, particularly if kept in insufficient numbers or in cramped conditions. This behaviour is most commonly directed at slow-moving, long-finned species such as bettas or angelfish. Maintaining a proper school size of six or more significantly reduces fin-nipping tendencies, as the fish direct their social interactions towards conspecifics rather than other tank mates.

Why are my Bleeding Heart Tetras losing their colour?

Colour loss in Bleeding Heart Tetras is usually a sign of stress, poor water quality, inadequate diet, or excessively bright lighting. Check your water parameters and ensure ammonia and nitrite are at zero and nitrate is below 20 ppm. Offer a varied diet including frozen and live foods, reduce lighting intensity, and ensure the fish are kept in an appropriately sized school. Illness can also cause colour fading, so observe the fish closely for any other symptoms.

Do Bleeding Heart Tetras jump out of the tank?

Yes, like many tetra species, Bleeding Heart Tetras are capable of jumping, especially when startled or stressed. A secure lid or cover glass is strongly recommended to prevent losses. This is particularly important during the first few weeks after the fish are introduced to a new tank, as they may be more prone to jumping while they are still settling in.

Related Guides

• Cardinal Tetra Care Guide – Another stunning South American tetra that thrives in similar soft, acidic water conditions and makes an excellent companion species.
• Rummy Nose Tetra Care Guide – A popular schooling tetra from the Amazon basin that shares the Bleeding Heart Tetra’s preference for warm, soft water.
• Ember Tetra Care Guide – A smaller tetra species ideal for nano and planted tanks, offering insight into tetra care at a different scale.
• Apistogramma cacatuoides Care Guide – A compatible dwarf cichlid that pairs well with Bleeding Heart Tetras in an Amazonian biotope setup.
• Corydoras sterbai Care Guide – A heat-tolerant bottom-dwelling catfish that complements mid-water tetras perfectly in a community tank.