Pristella Tetra

X-Ray Fish, Golden Pristella Tetra, Water Goldfinch

Family: Characidae Pristella Tetra, Pristella maxillaris, X-Ray Fish, Golden Pristella Tetra, Water GoldfinchPristella maxillarisPhoto © Animal-World Courtesy Louis Lessard
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I want to start my own tank, im new to having fish. this will be my first fish tank. I dont know what fish to start off with and what fish get alone with eachother.   michelle

The Pristella Tetra is a perky little fish that is social, friendly, and very easy to care for!

The Pristella Tetra Pristella maxillaris, also known as the Golden Pristella Tetra, is a very pretty little characin. Its known as the X-Ray Fish because its silvery yellow body that is quite transparent. It has striking fin coloration as well, with the dorsal and anal fins having a yellow stripe followed by a black stripe, and finally end up with a white tip, and the tail fin being red or pink. Other common names that describe this beauty range include Water Goldfinch, X-ray Tetra, and Pinktailed Tetra.

The Golden Pristella Tetra is an excellent fish for the beginner. It is extremely hardy and undemanding and is not at all choosy in its water type. That's probably because it is found naturally in both brackish water as well as soft water. It can even withstand very hard water, though it does do its best in soft. A dark substrate and subdued lighting will show the X-Ray Fish best and enhance its colors. It will not get its full color in hard water or under bright light.

The Pristella Tetra is easy to keep in other respects as well. Its a peaceful community member as well as being fairly prolific in breeding. It is also a very active schooling fish but is harmless to other fish and plants. A school of 6 or more of these characins is really striking when maintained in a heavily planted aquarium.

For Information on keeping freshwater fish, see:
Freshwater Aquarium Guide: Aquarium Setup and Care

Geographic Distribution
Pristella maxillaris
Data provided by
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Characiformes
  • Family: Characidae
  • Genus: Pristella
  • Species: maxillaris
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Pristella Tetra - Quick Aquarium Care
  • Aquarist Experience Level: Beginner
  • Size of fish - inches: 1.8 inches (4.50 cm)
  • Minimum Tank Size: 15 gal (57 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Very Hardy
  • Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)
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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 and 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 - 5 years or longer. It has a silvery to yellowish body, a large spot on the dorsal and anal fin, and a reddish tail. The dorsal and anal fins start out with a yellow stripe, changing to a black stripe, and finally end up with a white tip. Very striking.

An albino variety has also been developed and is also popular. It has pink eyes and pink spots, but a more washed out general body coloration. It is even easier to breed than the natural X-Ray Fish, which may be why it is also popular.

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

Fish Keeping Difficulty

The Pristella Tetra is a hardy fish that is great for the beginner fish keeper. This mass-produced fish is adaptable and will do well in most tank setups within reason. Keep the water quality high and a good water turn over 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 everyday. 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
  • 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 the water is kept clean. Aquariums are closed systems and regardless on size all need some maintenance. Over time decomposing organic matter, nitrates, and phosphate build up and the 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 - 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 six will do best in about a 15 - 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 likes a moderate amount of current. To accomplish this a can add a canister filter or powerhead can be added 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, removing and replacing every few weeks. To give these fish a real feeling of nature, add some aquarium safe peat to the filter which will simulate the black waters of their natural environment.

As a rule the characins do not tolerate salty water, but the Pristella Tetra is an exception. They are one characin species that naturally occurs in a variety of water conditions, including slightly brackish water that is mineral rich and has an alkaline pH. Still its tolerance of salt is not high. If keeping it in a low salinity brackish tank it can tolerate a salinity that is about 10% of a normal saltwater tank, a specific gravity of less than 1.0002. The specific gravity must be kept below 1.003 or they will die.

  • Minimum Tank Size: 15 gal (57 L) - A fifteen gallon is the smallest size that could house the small school this fish requires to be comfortable.
  • Suitable for Nano Tank: Yes
  • Substrate Type: Any
  • Lighting Needs: Moderate - normal lighting
  • Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)
  • Range ph: 6.0-8.0
  • Hardness Range: 2 - 30 dGH
  • Brackish: Sometimes - It can tolerate a low salinity brackish tank that is about 10% of a normal saltwater tank, a specific gravity of less than 1.0002.
  • Water Movement: Moderate
  • Water Region: All - These fish will swim in all areas of the aquarium.

Social Behaviors

Golden Pristella Tetra
Photo © Animal-World
Courtesy Steve Foss

The Pristella Tetra are very peaceful and a good community fish. They are ideal for a community aquarium with other peaceful fish. They can be kept in large schools and will do best if kept in a school of at least 6 individuals. Tetras can be easily spooked into hiding so situate the tank appropriately. The best tank mates for this fish are other small tetras, pencil fish, Corydoras, small rasboras, most livebearers and loaches.

In a slightly brackish water aquarium they can be housed with Kribensis Cichlids Pelvicachromis pulcher, Orange Chromide Cichlids Etroplus maculatus, small gobies and other small non-predatory fish.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species - conspecifics: Yes - A minimum school of 6, but more are better.
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Large Semi-Aggressive (): Threat
    • Large Aggressive, Predatory (): Threat
    • Slow Swimmers & Eaters (): Safe
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Safe

Sex: Sexual differences

The male is more slender with a sharply pointed swim bladder. The female is more rounded and you can actually see the eggs in a mature female.

Breeding / Reproduction

The Pristella Tetra fish are egg layers. The female will spawn 300-400 eggs. The hard part is finding a compatible pair since they seem to be picky about who their partner is and sometimes the male is just unresponsive. Other than that they are easy to breed. to See a general description of how to breed egg layers in Breeding Freshwater Fish: Characins.

  • Ease of Breeding: Moderate - It may take several attempts before a compatible breeding pair is established.

Fish Diseases

The Pristella Tetra is very hardy and disease is not usually a problem in a well maintained aquarium. That being said there is no guarantee that you won't have to deal with health problems or disease. Anything you add to your tank can bring disease to your tank. Not only other fish but plants, substrate, and decorations can harbor bacteria. Take great care and make sure to properly clean or quarantine anything that you add to an established tank so not to upset the balance.

A good thing about the Ornate Tetra is that due to their resilience, an outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. When keeping more sensitive types of fish, it is common for all fishes to be infected even before the first warning signs can be noticed. The best way to proactively prevent disease is to give your Flame Tetra the proper environment and give them a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. Stressed fish are more likely to acquire disease.

As with most fish they are prone to skin flukes, parasitic infestations (protozoa, worms, etc.), ichthyobodo infection, parasitic infestations (protozoa, worms, etc.), bacterial infections (general), and bacterial disease. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Pristella Tetra is readily available and moderately priced. It is also commonly sold as the X-Ray Fish, Golden Pristella Tetra, and X-ray Tetra.


Author: David Brough CFS, Clarice Brough CFS
Lastest Animal Stories on Pristella Tetra

michelle - 2012-10-22
I want to start my own tank, im new to having fish. this will be my first fish tank. I dont know what fish to start off with and what fish get alone with eachother.

  • Jeremy Roche - 2012-10-22
    What size tank are you starting with?  a 30 gallon is a good started tank. Good starter fish are swords, platies, guppies, mollies and a few other livebearers.  Cool thing about these as you will get a chance to watch them have babies!
Natalie - 2012-07-17
Will my x ray tetra spawn??? ( my tank is only 2.25 gallon ) I currently have 4 of them, 2 female and 1 male. I'm not sure about the other. The tank is shared with 3 red cherry shrimp, 3 golden tetra, 3 cardinal tetra and 1 panda cory. Tks in advance

  • symbol - 2012-08-30
    That sounds like a very crowded tank! It would be nice for them if you could space them out a little more. Also, I think that cory cats normally like to live in groups. Maybe you could get a bigger tank and get him some friends? I think it would be very difficult to breed fish in a 2.25 gallon tank. If you can get a bigger tank at some point, maybe you could try to find a compatible/breeding pair then.
  • Jeremy Roche - 2012-08-31
    Way to small of a tank!  Should have at least a 20 gallon tank.  To spawn they really need an open area and peace from other fish.  Normally a seperate tank is set up just for that purpose.  Some great info if you click the link uner reproduction
Anonymous - 2010-01-18
I just got 3 of these fish today, and I call them little taxi's.

  • yasmine - 2010-02-24
    Why did you call them fish taxis, but anyways I bought ten of them.
Learth Hoch - 2010-10-26
I have had my pristella tetras, Sushi, Sashimi, and Sailboat, for almost 3 weeks now. They are my first fish, and they are very hardy, very tolerant fish! They are active swimmers, and oh so very cute. :D I'm thinking about getting 2 or 3 more to swim with them in my 15 gallon, since they are schooling fish. And another thing--these little buggers are FAST! When I try to catch them when I clean the aquarium, they dart away surprisingly quickly. I call them, 'The Secret Society' hahaha. I love my pristellas. :D

  • bev - 2011-01-23
    I have 3 in my tank they are beautiful lil fish :) I keep them with white widows, black phantoms, red fin colombians, lemon albino, harlequins, glowlights, platys, pepper and albino corys, khuli loach, golden loach, a black common plec and a sailfin plec. They all get on together really well :D