Red phantom tetra (Hyphessobrycon sweglesi) care guide

Group
Freshwater fish
Other names
Hyphessobrycon sweglesi, Rubra phantom tetra
Family
Acestrorhamphidae (American tetras; formerly Characidae)
Origin
Upper and middle Río Orinoco basin in Colombia and Venezuela; small tributaries, oxbows, flooded forest and savanna streams, in clear and blackwater.
Water
freshwater
Maximum size
3.5 cm
Temperature
20–26°C
pH
5–7
Hardness
Soft, 1–12 dGH
Minimum tank
72 litres
Care level
intermediate
Temperament
peaceful

Care

A peaceful, richly coloured tetra for a quiet community tank. Keep at least 8–10, as the fish form temporary pecking orders and show better colour and behaviour in a proper group. A tank with a base of 80 × 30 cm (about 70 litres) is the minimum. Set it up with a sandy substrate, driftwood roots and branches and some dried leaf litter, or as a heavily planted tank. Dim lighting, floating plants and tannin-stained water all suit it and bring out the red. It does best in soft, acidic water: Seriously Fish gives 20–28°C, pH 4.5–7.5 and 1–12 dGH, while FishBase suggests cooler water of 20–23°C, so aim for the middle to lower 20s and a pH below neutral. It is a little less forgiving of hard, alkaline water than the black phantom. Several colour forms have been traded, including an intense 'red' or 'rubra' form whose colour holds in captivity. Most fish sold are commercially bred and wild ones are fairly scarce. It has recently been moved from Hyphessobrycon to the revived genus Megalamphodus. Wild populations come in at least three colour forms, from silvery and see-through to red, possibly depending on habitat. Sources: Seriously Fish (seriouslyfish.com/species/hyphessobrycon-sweglesi/); FishBase (fishbase.se/summary/Hyphessobrycon-sweglesi.html); Wikipedia (en.wikipedia.org/wiki/Megalamphodussweglesi). Checked October 2026.

Diet

Probably an omnivore feeding on small invertebrates in the wild. It will accept dried foods, but give a varied menu with regular live or frozen bloodworm, mosquito larvae, Daphnia and Moina for the best health and colour.

Breeding

An egg scatterer with no parental care. Use a dimly lit breeding tank with soft, acidic water and mesh on the bottom so the eggs fall through out of reach of the adults, then remove the parents after spawning. Start the fry on Paramecium or a very fine (5–50 micron) proprietary fry food, then move on to Artemia nauplii. Males develop longer dorsal and anal fins; females are deeper-bodied.

Compatibility and tank mates

Best with other small, peaceful fish that like soft water: similar-sized characins, pencilfish, hatchetfish, small catfish such as Corydoras and Otocinclus, and non-predatory dwarf cichlids. Avoid large, boisterous or predatory fish.

Last updated 4 October 2026. Community-edited care guide on Aquatic-Auctions.

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