Bleeding Heart Tetra Care Guide

The bleeding heart tetra is a deep-bodied, silvery-rose centrepiece tetra named for the single crimson blotch sitting over its heart — and it is not the peaceful nano shoaler its shelf-mates suggest. It grows to around 6 cm, lives longer than most tetras, and wants a real group of eight to ten in a long tank; under-grouped or housed with long-finned, slow fish it spars among its own males and nips fins. Buy it for a roomy, robust, fast-moving community, not a planted shrimp nano.

Bleeding Heart Tetra at a glance

The sourced figures the welfare engine uses to judge Bleeding Heart Tetra — the parseable key facts.

Where it comes from

Bleeding hearts come from the upper (western) Amazon basin around the 'Tres Fronteras' where Brazil, Peru and Colombia meet, in sluggish tributaries, side arms and forest lakes strewn with leaf litter, submerged wood and decaying vegetation. Field measurements there run remarkably soft and acidic — pH from roughly 3.8 to 6.4, very low conductivity, low oxygen, and water warming to nearly 30 °C in places. That origin sets the care: keep the water soft and slightly acidic, ideally with botanicals or leaf litter for colour and security; give gentle-to-moderate flow with plenty of cover and an open mid-water lane; and remember that this is a larger, deeper-bodied fish than a neon, so it wants footprint and length rather than a nano cube.

Did you know?

• The name is literal: a single crimson blotch sits over the fish's heart region on a silvery-rose deep body — one of the most recognisable single-spot markings in the hobby.
• It is a "big" tetra — at around 6.1 cm standard length it is roughly double a neon's length and far deeper-bodied, a centrepiece-scale fish rather than a nano.
• The male duels are a feature, not a bug. Rival males display and spar for status with flared fins — "interaction between rival males is fascinating to watch" — which is exactly why you keep a big group so the energy spreads harmlessly.
• It is one of three "bleeding hearts" routinely confused in shops, alongside H. socolofi and H. pyrrhonotus; the long white anal-fin band and the absence of red on the back are the tells for erythrostigma.
• A 2024 genus shuffle moved it from Hyphessobrycon to Megalamphodus (subfamily Megalamphodinae), so the scientific name on the science may lag the name on the shop label.
• IUCN Least Concern, assessed in 2021.

Tank size — and why

Plan for roughly a 30 US gallon, 90 cm-long tank as the practical floor for a proper group, not the 20 gallon some blogs allow for just four to six fish. The driver is the combination of adult body size (~6 cm, roughly double a neon and far deeper-bodied), active mid-water swimming, and — most importantly — group size: a longer footprint lets the school spread out, which diffuses male sparring and curbs fin-nipping. This is the core welfare reason for the space, more than bioload. Prioritise length over height, both for the swimming lane and to give displaying males room to settle a hierarchy, and fit a lid since it is an active tetra.

As a guide, a 30-gallon tank comfortably suits about 8–12 Bleeding Heart Tetra as a single-species display, leaving room for tankmates.

How big does it really get?

Full-grown Bleeding Heart Tetra reach about 6 cm (2.4 in) long, but they are usually sold at only about 2.5 cm (1 in) — a typical shop size (estimate). At full size, Bleeding Heart Tetra needs roughly a 30-gallon tank, about 76 cm long; a common 10-gallon starter kit is only about 51 cm.

Adult size is sourced; the shop size is a typical-juvenile estimate; tank length is approximate for a standard 30-gallon aquarium.

Water parameters in practice

Aim for soft to medium, slightly acidic water around pH 6.0–7.0 and about 24–27 °C. It is adaptable — tolerating roughly pH 4.0–7.5 and 21–28 °C — and a touch more cool-tolerant than warm-water cardinals or discus, but it is a normal tropical community fish, not a subtropical or coldwater one, so don't treat it like a Buenos Aires tetra. Most stock is captive-bred, which improves its tolerance, but it is still happiest soft and stable; avoid hard alkaline extremes and parameter swings, and a mature, cycled tank matters.

Diet & feeding

An opportunistic omnivore — in the wild it feeds on worms, crustaceans and plants. A good-quality flake or pellet with some plant content makes the base, topped up with small live or frozen foods such as bloodworm, daphnia and brine shrimp, plus the occasional plant matter, to deepen colour and bring it into breeding condition. Feed small amounts once or twice a day, only what is cleared in a few minutes. It is a competitive mid-water feeder, which makes it a useful dither fish but is also a reason not to mix it with timid, slow feeders that would be out-competed.

Gear & setup

A heater for the tropical setpoint, a filter giving gentle-to-moderate flow (its origin is sluggish forest water), dark substrate to deepen the colour and settle the fish, and a layout of driftwood, leaf litter or botanicals with planting around the sides and an open central swimming space. Floating plants for diffused light suit the shaded, tannin-stained biotope. A lid is sensible for this active swimmer.

Temperament & behaviour

Seriously Fish calls it generally peaceful and an ideal resident of the well-researched community aquarium — but adds, importantly, that adult males are territorial to an extent. Rival males display and spar for status with flared fins, which is normal, watchable, and largely harmless when the group is big enough, but in too small a group a dominant male will bully subordinates. The fish is also a conditional fin-nipper: it nips when stressed — kept singly, under-grouped, or alongside long-finned and slow tankmates — rather than relentlessly like a tiger barb. The fix is a proper group, space, and appropriate tankmates, all of which point in the same direction.

Group & social needs

A shoaling tetra that must be kept in a mixed-sex group of at least eight to ten — treat six as a bare floor. The reason is behavioural: a larger group spreads male display across more targets, settles the hierarchy, and curbs both the bullying and the fin-nipping. Under-stocked fish turn shy, withdrawn and nippy. This is one of the cases where the group-size rule is genuinely welfare-critical rather than cosmetic.

Compatible tank mates (preview)

A short, engine-cleared shortlist — the species TankStocking's welfare engine clears with Bleeding Heart Tetra and that suit its size and temperament best. Tap any to load the pairing in the planner.

• Black Neon Tetra — Peaceful temperament, similar adult size.
• Black Phantom Tetra — Peaceful temperament, similar adult size.
• Boesemani Rainbowfish — Peaceful temperament, similar adult size.

This engine-cleared shortlist is Bleeding Heart Tetra's tankmate surface for now — a dedicated tank-mates guide can follow for high-demand species.

Breeding & sexing

Sexing is clearer than in most tetras — males are larger and more intensely coloured, with an extended, sickle-shaped dorsal fin and elongated anal and pelvic fins, while females are rounder and fuller-bodied, especially when gravid. Breeding is moderate: harder than an easy egg-scatterer like a neon, but achievable. Use a separate, dimly lit spawning tank with very soft, acidic water and fine-leaved plants or a spawning mop, condition the pair on live foods, and raise the temperature slightly to trigger spawning. They scatter eggs and show no parental care, eating their own eggs, so remove the adults afterwards; raise the fry on infusoria-grade foods then microworm and baby brine shrimp, kept dim and clean.

Lifespan

Three to five years with good care — notably longer-lived than the nano tetras it sits beside in the shop, with the occasional claim of more in pristine conditions best treated as anecdotal. What shortens it is the predictable set: too small a group and the chronic stress that brings, a too-short tank, unstable or hard alkaline water, and fin rot secondary to the fin damage that follows poor tankmate choices.

Common mistakes

• Buying it as a "peaceful nano community" tetra. It is bigger (~6 cm), boisterous, and conditionally nippy — the single biggest conceptual error with this fish.
• Too small a group or too short a tank. One to six fish in a cramped 20 gallon turns into shy, bullied, fin-nipping fish; buy eight to ten for a 90 cm / ~30 gallon tank.
• Mixing with long-finned, slow fish — angelfish, bettas, fancy guppies, fancy gouramis, fancy goldfish. Their trailing fins are nip-bait, which is why those species are excluded from this fish's recommended tankmates even when a coarse size match would clear them.
• Mixing with timid, slow feeders. Shy nano fish and very peaceful species get out-competed at feeding and stressed by the active shoal.
• Hard alkaline water with no acclimation. It prefers soft, slightly acidic, stable water; avoid extremes and big swings.

Signs of trouble

• Fading of the deep rose colour, clamped fins and withdrawal from the shoal — usually an under-sized group, a too-short tank, or unstable water.
• Frayed or nipped fins, on the fish itself or on its tankmates, often followed by fin rot — the marker of a group that is too small or tankmates that are too long-finned.
• A single male relentlessly bullying subordinates rather than briefly sparring — a sign the group is too small to spread the display.
• White spots with flashing, or signs of fungus and flukes — the usual community-tetra ailments, almost all preventable with stable water and quarantine.

Is this fish right for you?

Don't buy bleeding hearts if you want a small nano or shrimp tank, if you can't house eight to ten in a 90 cm-plus tank, if your community is built around long-finned or delicate slow fish, or if you can't provide soft-ish, stable water. On stock quality the news is good: Wikipedia notes almost all the trade is captive-bred, so sourcing is generally sound — but skip obviously dyed or injected fish and any tank holding clamped-fin, white-spotted or curved-spined stock.

Bringing one home

Acclimate gently to its preferred soft, slightly acidic water — float to match temperature, then add tank water over about twenty minutes before netting the fish across. Add only to a mature, cycled, stable tank and quarantine new stock; given that fin damage and secondary fin rot are real risks for this fish, starting it in clean, settled water with the right group already in place pays off.

Common questions

Are bleeding heart tetras aggressive or fin-nippers?

They are generally peaceful but not pure angels. Adult males spar for status, and the fish is a conditional fin-nipper — it nips when kept singly, under-grouped, or alongside long-finned and slow tankmates, rather than relentlessly like a tiger barb. A proper group of eight to ten in a long tank, with robust tankmates, keeps it in check.

How many bleeding heart tetras should I keep, and in what size tank?

A mixed-sex group of at least eight to ten, in a roughly 30 US gallon / 90 cm-long tank; six and a 20 gallon are bare floors for four to six fish only. The larger group spreads male display and curbs fin-nipping, and the longer footprint gives them room to settle a hierarchy.

Can bleeding heart tetras live with angelfish, bettas or guppies?

No. Long-finned, slow fish — angelfish, bettas, fancy guppies, fancy gouramis and fancy goldfish — are prime fin-nip targets, so they are kept off this fish's recommended tankmate list. Pair bleeding hearts with fast, sturdy, similarly-sized fish instead.

How big do bleeding heart tetras get and how long do they live?

Around 6 cm — roughly double a neon and far deeper-bodied, a true centrepiece tetra — and they live about three to five years with good care, notably longer than most nano tetras.

What water conditions do bleeding heart tetras need?

Soft to medium, slightly acidic water around pH 6.0–7.0 and about 24–27 °C, stable rather than perfect. They tolerate a wider band (roughly pH 4.0–7.5, 21–28 °C) but are happiest soft; they are a normal tropical fish, not a coldwater one.

How do you tell male from female bleeding heart tetras?

Males are larger and more intensely coloured with an extended, sickle-shaped dorsal fin and elongated anal and pelvic fins; females are rounder and fuller-bodied, especially when carrying eggs.

Sources & confidence

Sources & confidence (9 species)

These back the Bleeding Heart Tetra figures and the previewed tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

• Bleeding Heart Tetra Hyphessobrycon erythrostigma — Seriously Fish (Hyphessobrycon erythrostigma) high confidence
• Black Neon Tetra Hyphessobrycon herbertaxelrodi — Seriously Fish / Aqua-Fish (Hyphessobrycon herbertaxelrodi) high confidence
• Black Phantom Tetra Hyphessobrycon megalopterus — Seriously Fish (Hyphessobrycon megalopterus) high confidence
• Boesemani Rainbowfish Melanotaenia boesemani — Seriously Fish; Aquarium Co-Op Boesemani guide high confidence
• Bolivian Ram Mikrogeophagus altispinosus — Seriously Fish (seriouslyfish.com/species/mikrogeophagus-altispinosus) high confidence
• Brilliant Rasbora Rasbora einthovenii — Seriously Fish (seriouslyfish.com/species/rasbora-einthovenii) high confidence
• Bronze Corydoras Corydoras aeneus — Seriously Fish (seriouslyfish.com/species/corydoras-aeneus) high confidence
• Cardinal Tetra Paracheirodon axelrodi — Seriously Fish (seriouslyfish.com/species/paracheirodon-axelrodi) high confidence
• Checker Barb Oliotius oligolepis — Seriously Fish — Oliotius oligolepis (https://www.seriouslyfish.com/species/oliotius-oligolepis/) high confidence

Care-guide sources (6)

This guide synthesises the references below; where they disagree, the range and the disagreement are noted in the text above. The figures in the key-facts box are read from the TankStocking species database (v2026.06). Full welfare model on the methodology page.

• FishBase — Megalamphodus erythrostigma — authority (Fowler 1943), current genus Megalamphodus / family Acestrorhamphidae, max 6.1 cm SL, temp 23–28 °C, pH 5.6–7.2, dH up to 12, upper Amazon range, IUCN Least Concern (2021), omnivore diet ("worms, crustaceans and plants"), groups of 5+/minimum 80 cm husbandry note
• Seriously Fish — Hyphessobrycon erythrostigma — family (Characidae), synonyms, Tres Fronteras range and biotope, wild water pH 3.8–6.4, 55–60 mm, temp 21–28 °C, pH 4.0–7.5, GH 18–215 ppm, 90×30 cm tank, group of 8–10, "generally peaceful… adult males territorial to an extent" plus male display, sexing, breeding, socolofi/pyrrhonotus look-alike tells
• Wikipedia — Bleeding heart tetra — Megalamphodus erythrostigma (Fowler 1943), 2024 reclassification from Hyphessobrycon, etymology ("red spot"), 6.1 cm SL, crimson flank spot + white anal-fin stripe, longer male fins, IUCN Least Concern, "almost all… captive-bred"
• Aquarium Source — Bleeding Heart Tetra 101 — size 2–3 in, lifespan 3–5 yr, fin-nipping when kept alone ("may get territorial and resort to fin-nipping others"), 20 gal floor / school 4–6, temp 72–80 °F, pH 6.0–6.5, diet, good/bad tankmates, sexing, moderate breeding, diseases (ich/fin rot/fungus/flukes)
• The Aquarium Guide — Bleeding Heart Tetra Care Guide — size up to ~3 in, lifespan 3–5 yr, fin-nipping when alone/stressed, 20 gal (4–6), temp 72–80 °F, pH ~6.5–7.0, hardness 3–12 dGH, diet, angelfish/goldfish flagged as bad tankmates, sexing (sickle dorsal/extended anal), breeding, diseases
• FishkeepingAdventure — Bleeding Heart Tetra — fin-nipping as a stress signal, explicit advice against long-finned tankmates (angelfish, bettas, guppies), pair with faster fish, group of 6+, 20 gal, temp 72–80 °F, pH 6.5–7.0, lifespan 3–5 yr

More on Bleeding Heart Tetra

Related guides on TankStocking — each scored by the same welfare engine as the planner.

This care guide is a sourced planning reference, not veterinary advice — individual fish, filtration and maintenance all matter. Cycle the tank, test your water, and observe your fish. How TankStocking works →