Easy
Black Phantom Tetra (Megalamphodus megalopterus)
23–28°C · pH 6–7.5 · 80L
£3.99
A warm red Colombian tetra for calm planted communities. Red Phantoms hold mid-water in a group, males sparring with raised dorsal fins, and stay a manageable 3-3.5cm. Best kept eight or more.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Product-photo provenance and any image-specific limitations are stated on the listing.
Megalamphodus sweglesi
Red Phantom Tetra are a shoaling species — they need 6+ to feel safe and show their full colour.
A warm red Colombian tetra for calm planted communities. Red Phantoms hold mid-water in a group, males sparring with raised dorsal fins, and stay a manageable 3-3.5cm. Best kept eight or more.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Product-photo provenance and any image-specific limitations are stated on the listing.
Maintain these water conditions for optimal health and vibrant colors
Red Phantom Tetras are the warm-coloured member of the phantom tetra group, and one of the most rewarding small shoaling fish you can put in a planted community aquarium. Listed by our supplier as Megalamphodus sweglesi and by current literature as Hyphessobrycon sweglesi, the Red Phantom is a very peaceful South American characin with a translucent red to amber body, a dark shoulder blotch behind the gill cover, and red-washed fins that males raise and spread when they display to one another. They stay small at around 3 to 3.5 cm, live for roughly five years with good care, and suit anyone building a calm, softly lit planted tank. If you are working through a red phantom tetra care guide, asking how to care for red phantom tetras, or comparing small red tetras for a community tank, this is a species worth taking seriously.
A good red phantom tetra tank setup is not complicated: a mature, well-filtered aquarium with gentle flow, soft light, planted cover and a proper group. Their red phantom tetra temperature range is broad, their red phantom tetra pH requirements are unusually forgiving, and the modest red phantom tetra tank size minimum puts them within reach of most home aquariums. They are a favourite for red phantom tetras for planted aquarium displays because red against green plants and dark wood is one of the strongest colour combinations in freshwater fishkeeping. For aquarists after colourful tetras for a community tank with genuinely peaceful behaviour and real shoaling movement, the Red Phantom is an excellent choice.
The Red Phantom Tetra is a Colombian and Venezuelan fish from the upper Río Orinoco basin, with the type locality given as the Río Muco in Colombia. That places it in a very different part of South America from the Black Phantom, which is a Bolivian and Brazilian fish — a distinction that matters, and one we come back to below.
The waters it comes from are the classic small tropical tributaries of the Orinoco system: shallow, slow-moving, shaded by bankside vegetation and often stained the colour of weak tea by tannins leaching out of fallen leaves and submerged wood. The substrate is typically sand and a deep bed of leaf litter. Light reaching the fish is filtered and low. Dissolved minerals are usually scarce, which is why the species tolerates water down to pH 4.5 in the wild-caught literature.
You do not need to build a full blackwater biotope to keep this fish well, but you do get a visible return on imitating two things: shade and leaf litter. Floating plants to cut the light, and a handful of catappa or oak leaves on the substrate, will deepen the red on a Red Phantom faster than any colour-enhancing food.
Understanding the habitat also explains the behaviour. These are small fish from an environment full of cover and full of things that eat small fish. Out in the open with nowhere to retreat to, they behave like prey — pale, tight, low in the tank. Given planted thickets, wood and shade to fall back on, the same fish will hold the middle of the aquarium confidently for most of the day. Aquascaping for a Red Phantom is not decoration, it is husbandry.
A settled adult Red Phantom is red to amber through the entire body, with a translucent quality that lets light pass through the flanks. Behind the gill cover sits a dark vertical shoulder blotch — the "phantom" marking shared across this group. The dorsal, anal, pelvic and caudal fins carry the same red, often deepening towards the edges. Freshly imported juveniles at the 2.5 to 3 cm size we receive them are noticeably paler, and it takes a few weeks of stable water, shade and varied food before the adult colour arrives. This is normal, and it is the single most common reason a new keeper thinks the fish they bought was mislabelled.
Sexing is straightforward once the group is mature. Adult males develop extended dorsal and anal fins — the dorsal in particular grows tall and pointed, and it is the fin they raise during display. Females are deeper through the body, especially when carrying eggs, and their fins remain shorter and rounder. In a group of eight or more you will be able to pick out the males within a few weeks, because they will be the ones spreading their fins at each other.
This is the comparison worth getting right, because the two fish are sold side by side in most UK shops and are regularly confused — including in published care sheets. They are two different species from two different river systems.
| Red Phantom Tetra | Black Phantom Tetra | |
|---|---|---|
| Species |
Megalamphodus sweglesi (Hyphessobrycon sweglesi) |
Megalamphodus megalopterus (Hyphessobrycon megalopterus) |
| Origin | Upper Río Orinoco basin — Colombia and Venezuela | Upper rio Madeira and upper rio Paraguai — Bolivia and Brazil |
| Body colour | Red to amber throughout | Smoky grey to silver |
| Shoulder mark | Dark vertical blotch | Bold black patch, often edged in pale iridescence |
| Male fins | Extended dorsal and anal, red | Enlarged pelvic, dorsal and anal, black |
| Female fins | Shorter, red | Shorter, reddish pelvic, anal and adipose |
| Max size | 30-35 mm | 30-36 mm |
| pH range | 4.5-7.5 | 5.0-7.0 |
Female Black Phantom Tetras have reddish pelvic, anal and adipose fins. Glimpsed quickly in a busy shop tank, a female Black Phantom looks like a red-finned phantom and gets called a Red Phantom. The reliable test is the body, not the fins: a Red Phantom is red right through the flanks, while a Black Phantom's body stays smoky grey no matter what colour its fins are.
Both species are peaceful, both suit a similar community, and there is no reason you cannot keep the two together — they simply need to be counted as two separate shoals, because each species shoals with its own kind. If you want the grey-and-black version alongside this one, see our Black Phantom Tetra listing, and the closely related Rosy Phantom Tetra from the same rosy tetra group.
The published minimum is an aquarium with base dimensions of 80 x 30 cm — around 70 litres in a typical tank of that footprint. Length matters more than volume for a shoaling fish: they use horizontal space, and a long shallow tank suits them better than a tall narrow one of the same capacity.
Build the layout in three parts:
Use a dark, fine substrate — sand or fine gravel — and add wood, botanicals or leaf litter if you like the look. Filtration should be mature and gentle: these are small fish from slow water, and a powerful outlet blasting across the tank will keep them pinned in a corner. A sponge filter or a well-baffled internal is ideal for a species tank; a modest external is fine in a community.
Red Phantom Tetras are recorded across a genuinely wide range, which makes them easier to accommodate than their blackwater origins suggest:
A tank held steadily at pH 7.4 will grow better fish than one swung between 6.0 and 7.5 by well-meant chemical adjustment. Work out what your tap water actually is, confirm it sits inside the ranges above, and then leave it alone. Weekly partial water changes with temperature-matched, dechlorinated water do more for these fish than any bottled additive.
Nitrate should be kept low with routine water changes, and ammonia and nitrite must read zero at all times. Small, thin-bodied tetras show water quality problems before larger fish do: clamped fins, faded colour and hanging near the surface are early warnings worth acting on.
In the wild these are micro-predators, taking small invertebrates, insect larvae and anything else of the right size drifting past. In the aquarium they are unfussy omnivores, but the difference between a well-fed Red Phantom and a flake-only one is visible in the colour.
Two small feeds a day beats one large one. Offer only what the shoal clears in about a minute, and run one lighter day a week. Overfeeding a small tetra is the quickest route to bloating and to nitrate problems in a modestly sized tank.
Watch the group at feeding time. A healthy Red Phantom feeds actively in mid-water without dashing frantically. Fish that consistently hang back are either being out-competed by bolder tank mates or are unwell, and both are worth investigating early.
This is a very peaceful species and a straightforward community fish, provided the community is a calm one. Good companions include:
Avoid anything large enough to eat a 3 cm fish, persistent fin nippers, and boisterous fast feeders that will monopolise food. Very hard-water fish such as most Rift Lake cichlids are a poor match on parameters alone, quite apart from temperament.
Adult shrimp are usually safe in a mature, heavily planted tank with plenty of moss. Shrimplets are not — a shoal of tetras will hunt them steadily, and a shrimp colony will stop recruiting. If breeding shrimp is the goal, keep the two in separate tanks.
Eight to ten is the minimum that works, and more is better. This is not a stocking guideline invented to sell fish; it changes what the animal does. In a group of three or four, Red Phantoms behave like prey: pale, tucked into planting, fins held down. In a group of ten or twelve, the males have rivals to display to, and the whole shoal holds open water with confidence.
Buy the group in one go rather than adding a few at a time. A shoal introduced together settles as a single social unit, and you avoid repeatedly disturbing established fish. If you plan to build up over time, add in blocks of at least four or five rather than singles.
Red Phantoms are egg-scattering free spawners with no parental care — the adults will eat the eggs given the chance, so a separate breeding tank is essential if you want fry.
This is not a difficult species to spawn by characin standards, but raising the fry needs patience, very clean water and small, frequent feeds.
With stable water and a proper group, expect around five years. The problems that do come up are nearly all husbandry-related rather than species-specific:
A settled group occupies the middle of the tank and moves as a loose shoal rather than a tight ball — tight shoaling in an aquarium is usually a sign of stress, not health. Through the day the males work out a rough hierarchy, meeting each other side on with the dorsal and anal fins raised and spread. It looks dramatic and it is almost entirely bluff; genuine damage is rare in a group with enough space and cover.
They are most active in the hours after the lights come on and again before they go off. Feeding brings the whole group forward. Between times they drift, pick at the water column, and use the planted margins as a retreat if something passes the tank. That mix of confident open-water presence and quick retreat is exactly what you are buying, and it only appears when the group is large enough and the layout gives them somewhere to fall back to.
The Red Phantom sits inside what ichthyologists call the rosy tetra clade — a cluster of closely related Hyphessobrycon species that share a deep, laterally compressed body, coloured fins and a similar temperament. They are constantly confused with one another in the trade, and because several are sold under overlapping common names it is worth knowing what separates them.
| Fish | Look | Temperament | Notes |
|---|---|---|---|
| Red Phantom | Translucent red-amber body, dark shoulder blotch, red fins | Very peaceful | Colombian; the warmest, softest red of the group |
| Rosy Tetra | Pink-silver body, red fins, often a white-tipped dorsal | Very peaceful | Larger and paler through the body |
| Ornate / Bentos Tetra | Pinkish body, long white-tipped dorsal in males | Peaceful | Sold under several names; a near-identical care sheet |
| Black Phantom | Smoky grey body, black shoulder patch | Very peaceful | Bolivian/Brazilian; females have reddish fins |
| Serpae Tetra | Deep blood-red body, black shoulder mark and black dorsal | Nippy | The one to be careful with — a known fin-nipper |
The practical point is the last row. Red Phantoms are frequently swapped for Serpae Tetras by shoppers who just want "a small red tetra", and the two behave very differently. A Serpae will nip long fins and harass slower tank mates; a Red Phantom will not. If a peaceful community is what you are building, the distinction matters more than the shade of red.
All of the rosy-clade species can be kept together in one aquarium, but they shoal with their own kind rather than mixing, so six of one and six of another gives you two small groups, not one group of twelve. Our Rosy Phantom Tetra and Black Phantom Tetra listings cover the other two phantoms if you want the set.
Red Phantoms are one of the species where the aquascape genuinely changes how good the fish look, so it is worth planning the layout around them rather than adding them to whatever tank already exists.
A dark background and a dark substrate do most of the work. Fish that can see a pale, reflective wall behind them stay light-coloured as camouflage; against dark surroundings the same fish deepens its red within days. Fine sand or dark fine gravel is ideal, and it also suits the tank mates you are most likely to pair them with.
A handful of catappa (Indian almond) or oak leaves on the substrate mimics the leaf-strewn creeks the species comes from. Tannins released as the leaves break down tint the water very slightly, soften it marginally, and — most usefully — cut the harshness of aquarium lighting. Alder cones and seed pods do the same job. Replace leaves as they decompose; the biofilm that grows on them is also a food source for shrimp and fry.
You do not need to rescape. The two cheapest changes that make the biggest difference are a dark background — even a sheet of dark card taped to the outside glass — and a layer of floating plants to cut the light. Most Red Phantom disappointment is a lighting problem, not a fish problem.
The single most common message we get about this species is that the fish arrived paler than the photo. Here is the honest timeline.
Fish bought at the 2.5-3 cm supplier size are juveniles. What you are buying is the adult fish they become, and that takes a season of good water and varied food. Nothing about that process can be accelerated by colour-enhancing foods; it is driven by maturity, security and diet quality.
Red Phantoms are not demanding, but they are small-bodied fish that show water quality problems early. A simple, consistent routine is worth more than an elaborate one:
Ammonia and nitrite should read zero at all times. If either is detectable, the aquarium is not fully cycled or the filter has been disturbed, and small tetras are among the first fish to suffer for it.
Buy them if: you have a mature, planted aquarium of at least 80 x 30 cm, you want warm colour and shoaling behaviour rather than speed and bustle, your other fish are calm, and you are prepared to buy a proper group in one go.
Look elsewhere if: the tank is brand new, the aquarium is dominated by large cichlids, barbs or anything that feeds aggressively, or you want a fish that will be at its best on the day it arrives. Red Phantoms reward patience specifically; that is the deal with this species.
For a similar colour in a smaller, faster-settling fish, the Ember Tetra is the obvious alternative. For a calm mid-water shoal in harder water, the Harlequin Rasbora is more forgiving.
Red Phantoms are a mid-water shoal, which means they occupy one layer of the tank and leave the other two free. Three worked examples, all built around a proper group:
A classic, low-conflict combination in which every fish uses a different part of the tank. Soft, slightly acidic water suits all three, and the Corydoras keep the open sand turned over. Add floating plants and leaf litter and this is close to a biotope.
The two shoals shoal separately and use the space differently: the rasboras sit slightly higher and move more, the phantoms hold station and display. It reads as a much busier tank than the fish count suggests.
Three closely related species with near-identical care requirements, each shoaling with its own kind. The visual contrast between the red, the grey and the pink is the point, and because all three come from the same clade there is no compatibility question to work through.
With a shoaling fish, it is nearly always better to have fewer species in bigger groups than more species in small ones. Twelve Red Phantoms and twelve rasboras will look and behave better than six each of four different tetras — and the four-species tank is the one that ends up looking restless and thin.
Everything on this page condensed, for anyone who has read enough and wants the short version before ordering.
Have the aquarium mature and running before the fish arrive — filter cycled, temperature stable, planting in place. On arrival, dim the room lights, float the bag to equalise temperature, then drip-acclimate slowly. Release the fish into a shaded tank and leave the lights off for the rest of the day.
Expect them to look pale and cautious for the first few days; that is normal after a journey. Feed lightly at first, then build up to a varied routine over the first week. Colour typically arrives over two to four weeks as the fish settle, and it will keep deepening for months as they mature. Resist the urge to intervene — shade, stability, a decent group and varied food will do the work.
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