Information, Characiformes (Characins), Freshwater fish, Species, Tetras

Pristella tetra “X-ray Tetra” (Pristella maxillaris)

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by Jason Matthews



Pristella Tetra is a vibrant and hardy fish species that is a popular choice among pet fish owners. The Pristella Tetra, also known as the “x-ray tetra” due to its translucent appearance, is a one-of-a-kind and fascinating species that will add beauty and interest to any aquarium. 

This article will provide an in-depth look at the Pristella Tetra, including its origin, appearance, size, genders, behavior, tank conditions, tankmates, diet, breeding, and common diseases, whether you’re a beginner or an intermediate pet fish owner. So sit back, relax, and learn everything there is to know about this incredible species.


Scientific Name: Pristella maxillaris
Common Names: Pristella tetra, X-ray Tetra
Life Expectancy: 5-7 years
Adult Size: Up to 5 cm (2 inch)


HabitatRivers & Basins
OriginSouth America
Care LevelEasy
Tank LevelMiddle to bottom
Minimum Tank Size10 gallons
Water pH5.5-7.0
Water Temperature22-28°C (72-82°F)
Water Hardness5-15 dGH
Tank MatesPeaceful community fish

Fun Fact Corner

One fun fact about Pristella Tetras is that they are known to have a unique ability to change color. Pristella Tetras will turn a bright yellow when excited or stressed, earning them the nickname “Golden Pristella Tetra.” This is due to the presence of xanthophores, a special pigment in their scales responsible for their yellow coloration. This distinguishing feature makes them a vibrant and exciting addition to any fish tank.


The Pristella Tetra, scientifically known as Pristella maxillaris, is a freshwater fish native to South America’s Orinoco and Essequibo basins. 

They have been discovered in Venezuela, Guyana, and Brazil. Pristella Tetras can be found in various habitats, including shallow rivers, swamps, and flooded forests.

This fish is not commonly seen in aquariums and was only imported to the United States in the early 1980s. However, it has become a popular and widely available species among pet fish enthusiasts. The Pristella Tetra is an excellent choice for novice and experienced fish keepers due to its hardiness and adaptability to many aquarium conditions.

Appearance & Size

It has a distinct, translucent appearance, with a silver-blue body and a yellowish-orange fin coloration. The Pristella Tetra’s most distinguishing feature is a prominent black spot on the base of the dorsal fin. The fish is known as an “x-ray tetra” because of this black spot.

The Pristella Tetra has a long, slender body with a slightly curved back. The dorsal and anal fins are forked, and the tail fin is elongated and pointed. The transparent fins of the Pristella Tetra are lined with a bright red color, making it stand out in any tank.

Males have slightly longer fins and more vibrant colors than females, who are more extensive and have a more rounded belly. Overall, the Pristella Tetra is a visually appealing fish that will pique the interest of any aquarium visitor.

The Pristella Tetra is a small fish species that typically grows about 1.5 inches long. They are small to medium-sized fish, ideal for smaller aquariums or as schooling fish in larger tanks.

Pristella Tetras are the same size in both sexes, with males and females reaching similar maturity levels. It is worth noting, however, that females may be slightly larger than males, as evidenced by their rounded somewhat bellies.

It’s important to remember that tank conditions, diet, and overall health can influence the size of Pristella Tetra in captivity. Proper tank maintenance, water quality, and a balanced diet can all help your Pristella Tetras grow to their full potential.


The Pristella Tetra is a fish species with sexual dimorphism, which means that males and females have distinct physical characteristics that allow easy identification. Males and females are roughly the same at maturity, with males slightly smaller. The fins are the most distinctive physical feature that distinguishes males from females.

Males have slightly longer fins and brighter colors, whereas females have a more rounded belly and duller colors.

It’s worth noting that in a group of Pristella Tetras, males tend to be more aggressive toward each other because they compete for females’ attention. Conversely, females are less aggressive and form smaller groups within larger groups of fish.

Keeping a ratio of one male to every two or three females is recommended to ensure proper breeding and maintain a healthy and balanced aquarium. This will help prevent aggressive behavior and allow all fish to breed.


They are known to be active swimmers who move around the tank, looking for food and interacting with their tank mates. They are also known as social fish, forming schools and swimming in unison with their peers.

One of the most noticeable characteristics of Pristella Tetras is their proclivity to jump out of the tank. Although this behavior does not harm the fish, it can annoy the aquarium owner. To prevent this, keep the water level in the tank high enough and cover the tank with a lid.


Regarding tankmates for Pristella Tetras, it’s important to choose fish of similar size and temperament. Pristella Tetras are peaceful and active fish that get along well with other friendly and active fish.

Here is a list of good tankmates for Pristella Tetras:

It’s important to keep in mind that Pristella Tetras are schooling fish and should be kept in groups of at least 6 individuals. As a result, when choosing tankmates, keep the tank size and the bioload of the other fish species in mind. It’s also worth noting that Pristella Tetras are sensitive to copper-based medications, so avoid tankmates who may require copper-based treatments.

Tank conditions

When it comes to tank conditions for Pristella Tetras, it’s important to provide them with a spacious aquarium that can accommodate their active swimming behavior. A tank of at least 20 gallons is recommended for a small group of Pristella Tetras, with larger tanks required for a larger group of fish.

Pristella Tetras require water temperatures of 72-82°F (22-28°C) and pH levels of 6.0-7.5. To ensure the health and well-being of the fish, it is critical to keep the water temperature and pH stable.

It’s also important to keep the tank’s water clean and well-oxygenated by providing adequate filtration and aeration. Regular water changes are also required to maintain water quality and the health of the fish.

Pristella Tetras prefer a well-planted tank with plenty of hiding places and open swimming space. They aren’t picky about the plants they eat, but it’s important to give them a variety of plants to encourage natural behavior and give the fish a sense of security.


When it comes to the diet of Pristella Tetras, it’s important to provide a varied diet to ensure that Pristella Tetras receive all of the nutrients they require for optimal health. Pristella Tetras are omnivorous, consuming both plant and animal-based foods. Pristella Tetras feed on various small aquatic invertebrates, including worms, crustaceans, insects, algae, and other plant material in the wild.

Pristella Tetras can be fed a variety of foods in the aquarium, including:

  • High-quality flake or pellet food specifically formulated for small tropical fish
  • Frozen or live foods such as brine shrimp, blood worms, or daphnia
  • Vegetable-based foods such as blanched spinach or peas

Furthermore, Pristella Tetras should be fed in small amounts 2-3 times per day, as overfeeding can lead to water quality and health problems.


Breeding Pristella Tetras can be a rewarding experience for those with experience in breeding tropical fish. Pristella Tetras are known for being relatively easy to breed in captivity. To reproduce Pristella Tetras, a separate breeding tank with the proper water conditions, such as a pH range of 6.0-7.0 and a water temperature of 74-78°F, is required. A mature and healthy pair of fish is also required, as is a suitable spawning substrate, such as fine-leaved plants or a spawning mop.

When the conditions are favorable, the female Pristella Tetra will lay her eggs on the spawning substrate, fertilized by the male. After the eggs are laid, the adult fish must be removed from the breeding tank to prevent them from eating.

The eggs will hatch in 24-36 hours, and the fry can swim freely in 3-4 days. They can be fed small amounts of infusoria or newly hatched brine shrimp at this stage. The fry can be fed various small foods as they grow, such as microworms or grindal worms.

It’s important to note that the breeding process requires patience and experience, and you should be prepared to deal with any problems that may arise, such as fungus or bacterial infections.


Regarding potential diseases that Pristella Tetras may face, it is important to note that they are generally hardy fish and are not prone to many illnesses. However, as with any aquatic species, keeping their tank clean and healthy is important to prevent disease spread. Ich, a parasitic infection that causes white spots on the fish’s body and fins, and Fin Rot, a bacterial infection that causes the fins to deteriorate and fray, are two common illnesses that can affect Pristella Tetras.

Furthermore, it is essential to ensure that the water parameters are within Pristella Tetras’ acceptable range and to avoid overfeeding, which can lead to poor water quality and disease spread. 

If you notice any illness, you should immediately isolate the affected fish and consult with an aquatic veterinarian. These illnesses are typically treatable with medication and a change in water conditions. It is also a good idea to consider a proper quarantine setup for all new fish before adding them to the community tank to reduce the risk of disease outbreaks.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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