Not furry, but we like them anyway.

Red Phantom Tetra

Megalamphodus sweglesi

Also called Hyphessobrycon sweglesi (former name), Megalamphodus sweglesi

SpeciesShort profile

From South America: upper and middle Río Orinoco basin in Colombia and Venezuela, including the Meta, Arauca, Apure and Cinaruco tributaries1 2 3

At a glance the quick version

Length3.2 to 3.5 cm2 1 3

Sizesmall

Very peaceful and suited to community tanks

Warm red colour that holds well in captivity

Small size suits modest aquariums

1 3

Looks how to spot one

Small, slender scaled characin

A slim little tetra whose colour ranges from a see-through silvery form to a rich red one, depending on where the fish come from. There is a dark spot just behind the head, and females carry a dark dorsal fin edged in cream. Mature males grow longer dorsal and anal fins.1 3

Coloursdeep red ('rubra' form)paler silvery-red formdark shoulder spotblack and cream dorsal fin (females)1 3

Personality what they are like

A calm, sociable tetra that gets along well with other small, gentle fish. Males hold small displays with each other within the group.1

Daily activity how busy a day looks

Moves around actively in the middle water layers and appreciates both open water and plant cover.1 3

Grooming and care the hands-on bits

Undemanding with stable, clean water and a varied diet; regular partial water changes help keep it in top colour.1

Home where they are happiest

Tank with a base of at least about 80 x 30 cm (around 72 litres); FishBase gives 60 cm as a minimum length. Temperature from about 20 to 28 °C (FishBase lists 20 to 23 °C), pH roughly 4.5 to 7.5, soft water (1 to 12 dGH). In nature it lives among submerged plants in clear or tea-stained water.1 2 3

Food basics what goes in the bowl

Omnivore. Accepts dried foods, but does best with a mix that includes small live and frozen foods such as bloodworm and Daphnia.1 2

Company who they like around

Shoaling fish: at least 5 individuals, preferably a group of 8 to 10 or more, with similar-sized peaceful species.1 2

The story where it all began

French ichthyologist Jacques Géry described the species in 1961, naming it after Kyle Swegles, a tropical fish dealer who collected the first specimens in the upper Orinoco. It has since been shifted between the genera Megalamphodus and Hyphessobrycon and is currently placed in Megalamphodus.2 1 3

Fun facts for the dinner table

1
Its scientific name honours Kyle Swegles, the fish trader who collected the type specimens.2
2
At least three colour forms are known, from almost transparent silvery fish to strongly red ones.3
3
Unlike some red fish that fade in aquariums, its red colouring tends to last in captivity.1
4
Females are easy to spot by the dark, cream-edged stripe on the dorsal fin.3

Recognised by the official bits

IUCN Red List: Least Concern (assessed 16 November 2020)2
FishBase: Listed as a commercial aquarium species2

The care rhythm a typical week and year

A typical home-care rhythm for a Red Phantom Tetra. A starting point, not a vet's advice.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Water changeAbout 25% of the waterevery week
Water testevery week
Glass cleanevery week
Filter rinseRinse in old tank water, never tap waterevery month

Owner questions the things everyone asks

How often should I feed my Red Phantom Tetra?

Feed small amounts once or twice a day, as Furry Diary's starting plan suggests. Offer only what they can eat in a couple of minutes to keep the water clean.1 Pet Wiki plan

What does a Red Phantom Tetra eat, and what should it never eat?

They are omnivores and enjoy dried foods, but thrive with small live or frozen treats like bloodworm and Daphnia. Avoid any foods that are too large or not designed for small fish, and never feed them human food or anything with additives.1 2

How much space does a Red Phantom Tetra need?

A tank with a base of at least 80 x 30 cm (around 72 litres) is recommended, though FishBase gives 60 cm as a minimum length. Provide open swimming space with plant cover for their active mid-water lifestyle.1 2 3

What temperature, light or water does a Red Phantom Tetra need?

Keep the water temperature between 20 and 28 °C (FishBase lists 20 to 23 °C), with a pH of 4.5 to 7.5 and soft water (1 to 12 dGH). They appreciate moderate lighting and a planted tank with clear or tea-stained water.1 2 3

How often should I clean a Red Phantom Tetra's home?

Furry Diary's starting plan recommends a 25% water change every week, along with weekly glass cleaning and water testing. Rinse the filter monthly in old tank water, never tap water. Pet Wiki plan

Can a Red Phantom Tetra live with others?

Yes, they are calm and sociable, best kept in a shoal of at least 5, preferably 8 to 10 or more. They get along well with other small, gentle fish of similar size.1 2

How long does a Red Phantom Tetra live?

With good care, they can live for several years, but exact lifespan varies. For a more precise estimate, ask a good breeder or an exotic-pet vet.

Can I handle a Red Phantom Tetra?

No, these delicate fish should never be handled. They are best observed in the tank, as handling can stress or injure them.1

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

Black Phantom Tetra

Rosy Tetra

Flame Tetra

Where this comes from

Every fact on this page has a numbered source. Spotted an error? [email protected].

Seriously Fish: Hyphessobrycon sweglesi seriouslyfish.comused for range, size, care parameters, diet, behaviour, colour forms, history
FishBase: Megalamphodus sweglesi fishbase.seused for distribution, max length, water parameters, IUCN status, etymology
Wikipedia: Red phantom tetra en.wikipedia.orgused for appearance, habitat, colour forms, taxonomy

Checked 2026-09-30. Text is written in our own words from these sources.