X-Ray Tetra - Pristella maxillaris

X-Ray Tetra (Pristella maxillaris)

The X-Ray Tetra is a hardy, peaceful and attractive freshwater shoaling fish, named for its translucent body that gives it a delicate “x-ray” appearance. It is also recognised by its black, white and yellow fin markings, subtle silver sheen and active mid-water swimming behaviour. Also known as the Pristella Tetra or Golden Pristella Tetra in its colour forms, this species is an excellent choice for mature community aquariums and is more adaptable than many delicate soft-water tetras.

Common Name:
X-Ray Tetra. Also commonly referred to as Xray Tetra, Pristella Tetra, X-Ray Fish, Water Goldfinch or Golden Pristella Tetra for the gold variety.

Scientific Name (Latin):
Pristella maxillaris

Maximum Size:
Around 4–5 cm in captivity, with FishBase listing up to 4.5 cm total length.

Water Type:
Freshwater

Origin / Natural Habitat:
Native to South America, including the Amazon, Orinoco and coastal river drainages of the Guianas. In the wild, X-Ray Tetras occur in calm coastal waters, densely vegetated swamps and slow-moving freshwater habitats. They are naturally gregarious and non-aggressive, often living in groups among plant cover and open swimming areas.

Water Parameters:
Temperature: 24–28°C
pH Range: 6.0–8.0
Hardness: soft to hard water tolerated, with stable conditions more important than chasing exact numbers

Temperament:
Very peaceful and social. X-Ray Tetras are excellent community fish and should be kept with other calm species of similar size and temperament. Avoid large, aggressive or predatory fish that may intimidate or eat them.

Diet:
Omnivorous micro-feeder. In nature, this species feeds on worms, small crustaceans and insects. In the aquarium it should be offered quality fine flake, micro pellets, crushed granules, frozen daphnia, cyclops, baby brineshrimp, bloodworm and occasional small live foods.

Minimum Tank Size:
A practical recommendation is at least 60 litres for a proper group, with a 60 cm aquarium or larger preferred for natural shoaling and active swimming behaviour.

Behaviour & Activity:
This is an active mid-to-upper level shoaling fish that should be kept in a group of at least 6, ideally 8–10 or more. In good numbers, X-Ray Tetras become more confident, display better colour and behave more naturally. They appreciate planted areas, open swimming space, gentle to moderate flow and darker décor that helps show off their translucent body and fin markings.

Aquarium Category:
Community Fish
This species is well suited to peaceful community aquariums with small-to-medium calm tank mates. Suitable companions include Neon Tetras, Cardinal Tetras, Black Neon Tetras, Harlequin Rasboras, Corydoras, Otocinclus, dwarf cichlids, small gouramis, pencilfish and other non-aggressive community fish. Avoid fin nippers, large predators, aggressive cichlids and very boisterous species that may stress the group.

Special Requirements or Care Notes:
Best kept in a mature, well-filtered aquarium with clean water, stable parameters and regular maintenance. X-Ray Tetras are relatively hardy and tolerant compared with many tetras, but they still need good water quality and should not be added to unstable new aquariums. A secure lid is recommended, as active tetras may jump when startled. The gold colour form is a captive-bred variety and has the same general care requirements.

Suitable for:
Beginner to intermediate fishkeepers

Availability:
Common in trade, usually as captive-bred stock

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.