Tetra- pristella (X-ray Fish)

Tetra- pristella (X-ray Fish)

Regular price $2.99 now $2.49 Unit price  per 

Shipping calculated at checkout.

The Pristella Tetra Pristella maxillaris is a very pretty little characin. It's known as the X-Ray Fish because its silvery yellow body is quite transparent. It has striking fin coloration. Its dorsal and anal fins have white tips and a striking stripe pattern of a yellow stripe followed by a black stripe. The tail fin is either red or pink. A popular albino variety has also been developed that is more subdued in color overall, but has pink eyes and pink spots. Other common names that describe this beauty include Golden Pristella Tetra, Water Goldfinch, X-ray Tetra, and Pinktailed Tetra.

This popular aquarium fish is the only species in the Pristella genus, and all specimens available in the hobby are commercially bred. In nature the Pristella Tetra inhabits the northeastern coastal waters of South America. During the dry season it lives in streams and tributaries. Then during the rainy season, it moves with the rising waters onto the savannah, where it spawns among the flooded vegetation.

Habitat: Distribution / Background

The Pristella Tetra Pristella maxillaris was described by Ulrey in1894. This species is not listed on the IUCN Red List. They are found in South America in Venezuela, British Guyana, lower Brazilian Amazon, Orinoco, and coastal river drainages of the Guianas. Other common names they are known by include X-Ray Fish, Golden Pristella Tetra, Water Goldfinch, X-ray Tetra, and Pinktailed Tetra.

They inhabit coastal waters that are often brackish. During the dry season, this tetra lives in clearwater streams and tributaries, but once the rainy season comes, the Pristella migrates into the flooded areas of the savannah to spawn in the thick vegetation. They swim in schools in densely vegetated swamps where they feed on worms, small crustaceans, and insects.

  • Scientific Name: Pristella maxillaris
  • Social Grouping: Groups
  • IUCN Red List: NE - Not Evaluated or not listed


The Pristella Tetra or X-Ray Fish is a deep-bodied tetra species. This fish will generally reach about 1 3/4 inches (4.5 cm) in length and has a lifespan of about 4 to 5 years, or even longer. Its silvery to yellowish body features a large spot on the dorsal and anal fin, and a reddish tail. The dorsal and anal fins start with a yellow stripe that changes to a black stripe and ends at a white tip. This is a very striking tetra.

Golden Pristella Tetra, Pristella maxillaris
Photo © Animal-World: Courtesy Steve Foss


This is a very striking tetra. it is also called X-ray Tetra and Pinktailed Tetra, and specimens that have a stronger golden cast inspired the common names Golden Pristella Tetra and Water Goldfinch.

A popular albino variety has also been developed. The Albino Pristella Tetra, also known as the Golden X-ray Tetra, has pink eyes and pink spots, but a more washed-out body coloration. The albino version is even easier to breed than the natural X-Ray Fish, which may explain its popularity.

  • Size of fish - inches: 1.8 inches (4.50 cm)
  • Lifespan: 5 years - These fish have a lifespan of 4 to 5 years or more.

 --Fish Keeping Difficulty

The Pristella Tetra is a hardy fish that is great for the beginning fish keeper, and all available specimens are commercially bred. This mass-produced fish is adaptable and will do well in most tank setups, within reason. Keep their water quality high with a good current, and these fish will do great.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner

 --Foods and Feeding

Since they are omnivorous, the X-Ray Tetra will generally eat all kinds of live, fresh, and flake foods. To keep a good balance, give them a high quality flake food every day. Feed brine shrimp (either live or frozen) or blood worms as a treat. These tetras like several feedings a day, but offer only what they can consume in 3 minutes or less at each feeding.

  • Diet Type: Omnivore - This fish should be fed a rich and diverse diet to promote good coloration.
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

 --Aquarium Care

The Pristella Tetra is easy to care for provided their water is kept clean. Aquariums are closed systems, and regardless of size, all need some maintenance. Over time, decomposing organic matter, nitrates, and phosphate build up, and water hardness increases due to evaporation. To combat these ever-changing conditions, water should be replaced on a regular basis, especially if the tank is densely stocked. At least 25 to 50% of the tank water should be replaced every other week.

  • Water Changes: Bi-weekly

 --Aquarium Setup

These fish are fairly hardy, and a school of 6 will do best in about a 15 to 20 gallon aquarium. The aquarium should be heavily planted around the sides and back and have plenty of open water for swimming in the front. A few hiding places would also be appreciated. These fish like a moderate amount of current. Add a canister filter or powerhead to create the proper current. The tank should have moderate to dim lighting.

A biotype setup is a great choice for this tetra and is very easy to put together. For the substrate, use a river sand with some driftwood and twisted roots scattered for cover. Add a few handfuls of dried leaves, and remove and replace them every few weeks. To give these fish a real feeling of nature, add some aquarium-safe peat to the filter to simulate the black waters of their natural environment.