X-Ray Tetra (Pristella Maxillaris): A Thorough Guide to Care and Compatibility

pristella tetra
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Last Updated: May 3, 2023 by Flora Gibbins

Imagine a group of freshwater fish shimmering with an almost ethereal glow, their bodies shimmering, one moment reflecting metallic gold and silver hues, and the next moment transparent, giving you glimpses of their spines and secrets.

They dart around, full of life, bringing a burst of energy to their surroundings. Now, wouldn’t that make a fascinating addition to your fish tank? Those vibrant creatures I’m describing are none other than Pristella Tetras, also known as X-Ray Tetras due to their unique, almost transparent bodies.

I must share a fascinating fact about these little wonders before we swim any further. Did you know the Pristella Tetra is one of the few species of fish that can adapt to both soft and hard water conditions? That means it’s not only beautiful and fun to watch but also a remarkably hardy fish. Stick with me, and you’ll find out why they could be the perfect addition to your aquarium.

X-Ray Tetra Facts and Overview

  • Common names: Pristella Tetra, X-Ray Tetra, X-Ray Fish, Golden Pristella Tetra (for the color variant)
  • Scientific name: Pristella maxillaris
  • Adult size: Approximately 1.5 to 2 inches (3.8 to 5 cm) in length
  • Lifespan: Typically 3 to 5 years, but some have been known to live longer in optimal conditions
  • Colors and Markings: A mix of silvery-transparent body with black, yellow, and white bands on the fins, and hints of blue and red on their tails
  • Origin: Found in the Amazon River Basin, Orinoco River Basin, and coastal rivers of the Guianas in South America

Origin and Distribution

So, where do these popular freshwater fish come from? They hail from the beautiful and diverse continent of South America. You’ll find them in various aquatic environments, like the Amazon River Basin, Orinoco River Basin, and coastal rivers of the Guianas. These fish love slow-moving or stagnant waters, where they can swim around, play hide-and-seek among the dense vegetation, and stay safe from predators.

Now, here’s something I find truly incredible about these fish: their adaptability to different water conditions. I mean, it’s not every day that you find a fish that can thrive in both soft, acidic waters and hard, alkaline waters, right? And that’s precisely what makes Pristella Tetras such superstars in the aquarium world.

These little guys have been charming fish enthusiasts since the early 20th century and have been commercially bred since then, and it’s not hard to see why. Their resilience, stunning looks, and peaceful nature make them an irresistible addition to community tanks. Trust me, if you’re thinking about starting a freshwater aquarium, you can’t go wrong with this species!


Alright, let’s talk about what makes Pristella Tetras so eye-catching! You know, the first time I saw these little beauties, I couldn’t help but be mesmerized by their appearance. There’s just something so enchanting about their transparent, almost ghostly bodies and the dazzling colors that dance along their fins.

These small fish grow to about 1.5 to 2 inches (3.8 to 5 cm) in length, but don’t let their size fool you. They’re packed with personality and stunning features that make them impossible to ignore. Their bodies are mostly transparent, which is why they’re often called X-Ray Tetras. This unique quality allows you to see their bones and internal organs, giving them an almost otherworldly look.

But wait, there’s more! The fins of the Pristella Tetra are adorned with striking bands of black, yellow, and white. The tips of its dorsal and anal fins have a touch of bright red, while its tail boasts iridescent hints of blue. It’s this combination of colors and their almost ethereal glow that makes this fish stand out in any aquarium.

There’s also a color variant called the Golden Pristella Tetra, which sports a beautiful golden hue instead of the silvery transparency. These golden wonders are just as captivating and make a fantastic addition to any tank, especially if you’re looking to mix things up a bit.

Behavior and Temperament

Now that we’ve covered their striking appearance, let’s dive into the behavior and temperament of X-Ray Tetras. Trust me, you’re going to fall in love with these little fish even more after hearing about their delightful personalities!

First things first, they are schooling fish. They absolutely love hanging out with their buddies and swimming around the tank together. In fact, they can get pretty stressed if they’re kept alone or in small groups. So, to keep them happy and healthy, make sure to have at least 6 to 8 Pristella Tetras in your aquarium. The more, the merrier!

One thing I’ve noticed about these fish is how peaceful they are. They’re super easy-going and get along well with other non-aggressive tank mates. You’ll often see them swimming in the middle to upper levels of the tank, playfully darting around, and exploring their surroundings. They’re such a joy to watch, especially when they start showing off their colors and engaging in their quirky swimming patterns.

But don’t worry, Pristella Tetras aren’t all play and no rest. They do have their chill moments, too. Sometimes, they’ll just float near plants or other hiding spots, taking a break and observing the world around them. It’s during these quieter moments that you can really appreciate their unique beauty.

Pristella Tetra Tank Mates

One of the most exciting aspects of setting up a community tank is choosing tank mates for your fish. Since Pristella Tetras, or X-Ray Tetras, are peaceful and sociable freshwater fish, they can happily coexist with a variety of other species. Let’s explore the different types of tank companions that would be suitable for your fish.

Compatible Fish Species

When selecting neighbors for your X-Raty Tetras, it’s essential to choose fish that have similar temperaments and water requirements. Some compatible fish species include:

  • Other Tetra species, like Neon Tetras, Cardinal Tetras, or Red Phantom Tetras
  • Other South American aquarium fish like pencil fish
  • Rasboras, such as Harlequin Rasboras or Chili Rasboras
  • Corydoras Catfish, which are peaceful bottom dwellers that complement the Pristella maxillaris‘ mid-to-upper level swimming habits
  • Guppies, Mollies, or Platies, which are all friendly and colorful additions to your tank
  • Dwarf Gouramis, whose calm nature pairs well with the X-Ray Tetras
  • Small, peaceful species of Loaches, like Kuhli Loaches

Non-Fish Tank Mates

X Ray Tetras can also share their tank with some non-fish critters. These invertebrates can help maintain your tank’s cleanliness and add more diversity to your aquatic ecosystem:

  • Shrimp, like Cherry Shrimp, Amano Shrimp, or Ghost Shrimp
  • Snails, such as Nerite Snails, Mystery Snails, or Malaysian Trumpet Snails

Tank Mates to Avoid

While Pristella Tetras get along with many species, there are some fish that you should avoid housing with them. Generally, it’s best to steer clear of large, aggressive, or predatory fish, as they can stress or harm your X-Ray Tetras. Some examples of fish to avoid include:

  • Cichlids, especially larger or aggressive species like the Jack Dempsey or Oscar
  • Large catfish, such as Redtail Catfish or Pictus Catfish
  • Aggressive species of Barbs, like the Tiger Barb
  • Large, predatory fish like Arowanas or predatory catfish

x-ray tetra

Pristella Tetra Care

Now that we’ve covered the basic information about Pristella maxillaris as a species, it’s time for us to dive into their care together. I’ve learned that providing the right care for your X-Ray Tetras will ensure they lead healthy, happy lives, and will also help them showcase their stunning colors and playful behavior. Trust me, it’s worth the effort!

In this section, we’ll cover essential aspects of Pristella Tetra care, including tank setup, water parameters, diet, and common health issues. So, let’s get started on this journey together and make sure your little fish friends feel right at home in their new aquatic haven!

Tank Setup

Creating a comfortable and stimulating environment for your X-Ray Tetras, is crucial to their well-being. A well-thought-out tank setup will mimic their natural environment, ensuring they feel secure and can engage in their natural behaviors. Let’s discuss the tank size, what to put in the tank, and necessary equipment and accessories to create the perfect home for your fish.

A. Tank Size

Pristella Tetras are relatively small fish, but they’re also active swimmers that need ample space to move around. A minimum tank size of 10 gallons is recommended, but if you can go larger, that’s even better, especially if you plan to have a community tank with other fish species. A larger tank will also help maintain stable water conditions, which is essential to the health of your fish.

B. What to Put in the Tank

To create a natural and enriching environment for your Pristella Tetra fish, consider the following when decorating your tank:

  • Plants: Live aquatic plants, such as Amazon Swords, Java Fern, or Anubias, provide hiding spots, improve water quality, and make your fish feel more at home. They also contribute to the overall aesthetics of your home aquarium.
  • Substrate: A dark, fine-grained substrate, like sand or fine gravel, will mimic their natural habitat and make their colors pop.
  • Hardscape: Driftwood, rocks, and other decorations will create additional hiding spaces and provide visual interest for your X-Ray Tetras.

C. Equipment and Accessories

To maintain a healthy environment for your Pristella Tetras, you’ll need some essential equipment and accessories:

  • Filtration: A good quality filter is crucial for maintaining water quality and removing toxins. Choose one with adjustable flow, as these fish prefer gentle water movement.
  • Heater: Since these are tropical fish, you’ll need a heater to maintain a stable water temperature. Aim for a temperature between 72°F and 78°F (22°C to 26°C).
  • Lighting: Moderate lighting will make your fish more comfortable and help live plants grow. Consider using a timer to create a consistent day-night cycle.
  • Thermometer: To ensure the water temperature remains within the ideal range, use a reliable aquarium thermometer.
  • Test Kits: Regularly test the water for ammonia, nitrite, nitrate, and pH levels to keep your fish healthy.

Water Parameters

Maintaining the right water parameters is essential for the well-being of your Pristella Tetras, or X-Ray Tetras. One thing I love about these fish is their adaptability to a range of water conditions, which makes them ideal for both beginners and experienced aquarists. However, it’s still important to ensure their environment remains stable and comfortable. Let’s take a look at the ideal water parameters for them:

  • Temperature: These are tropical fish, so they need warm water. Aim to keep the temperature between 72°F and 78°F (22°C to 26°C). A reliable heater and thermometer will help you maintain a stable temperature.
  • pH Level: These tetras can adapt to a range of pH levels, but they prefer slightly acidic to neutral water. Aim for a pH between 6.0 to 7.5. Regularly testing your water and making adjustments as needed will ensure a healthy environment for your fish.
  • Hardness: These fish can tolerate a wide range of water hardness levels. A general hardness (GH) of 5 to 19 dGH and a carbonate hardness (KH) of 3 to 12 dKH is ideal.
  • Ammonia, Nitrite, and Nitrate: As with any aquarium, it’s essential to keep ammonia and nitrite levels at 0 ppm. Nitrates should be kept below 30 ppm, but ideally below 20 ppm. Regular water testing and maintenance, like water changes and filter cleaning, will help you maintain these parameters.
  • Water Changes: I recommend performing regular water changes, around 25% to 30% every two weeks, to keep the water quality high and remove excess waste. This will help maintain a healthy and stable environment for your X-Ray Tetras.

Diet and Feeding

Feeding your Pristella Tetras a balanced and varied diet is vital to keep them healthy and vibrant. The good news is that they’re not picky eaters! These little fish are omnivorous, which means they’ll eat both plant-based and meaty foods. To help your fish thrive, let’s discuss their dietary needs and feeding habits.

  • Types of Food: A high-quality flake or pellet food should be the staple of your X Ray Tetra fish’s diet, as it provides essential nutrients. But variety is the spice of life, right? So, I recommend supplementing their diet with frozen or live foods like brine shrimp, daphnia, or bloodworms. This will not only provide additional nutrition but also keep your fish interested and excited during mealtime.
  • Feeding Frequency: I’ve found that it’s best to feed your Pristella maxillaris small amounts of food two to three times a day. Give them just enough food that they can consume within 2 to 3 minutes. This will prevent overfeeding and help maintain water quality.
  • Vegetable Matter: While X-Ray Tetras do enjoy meaty foods, it’s important not to forget about their need for plant-based nutrition. Including vegetable matter, like blanched spinach or spirulina flakes, in their diet can help improve their overall health.
  • Feeding Tips: To ensure all your X-Ray Tetras get enough food, try using a mix of floating and sinking foods. This way, both top and mid-level feeders can eat comfortably without competing too much for their meals.

Common Health Issues and Diseases

Any aquarium keeper would occasionally need to deal with sick fish. Hardy and resilient as they are, X-Ray Tetras can still be susceptible to certain health issues and diseases. By understanding the signs and symptoms, you’ll be better equipped to prevent, identify, and treat these conditions, ensuring your fish stay happy and healthy. Here are some common health issues that you might encounter:

  • Ich: Ich, also known as White Spot Disease, is a common parasitic infection that can affect many fish species. It presents as tiny white spots on the fish’s body, fins, and gills. If you notice any signs of Ich, increase the water temperature to around 82°F (28°C) for a few days and use over-the-counter Ich medication to treat the infection.
  • Fin Rot: Fin Rot is a bacterial or fungal infection that causes the fins to become ragged and discolored. Maintaining good water quality and avoiding stress to your fish can help prevent Fin Rot. If you suspect an infection, treat the tank with a broad-spectrum antibiotic or antifungal medication.
  • Swim Bladder Disease: This condition affects a fish’s ability to maintain buoyancy and can be caused by overfeeding, constipation, or poor water quality. Affected fish may have difficulty swimming or may float at odd angles. To treat Swim Bladder Disease, fast your fish for a day or two and then feed them a diet rich in fiber, like blanched peas.
  • Internal Parasites: Internal parasites, such as worms or protozoa, can cause weight loss, lethargy, and bloating in your fish. Regularly feeding your fish a balanced diet and maintaining water quality can help prevent internal parasites. If you suspect an issue, consult with your local fish store or a veterinarian for appropriate treatment options.

To minimize the risk of disease, it’s essential to maintain a clean, stable environment for your Pristella Tetras. Regular water testing, water changes, and feeding a balanced diet will help keep your fish healthy and less susceptible to illness. It’s also important to quarantine any new fish that you’ll add to your tank to prevent the spread of sickness.

pristella tetra, x-ray tetra

Breeding X-Ray Tetras

Are you considering breeding your X-Ray Tetras? It can be a rewarding experience and a great way to deepen your understanding of these beautiful fish. With some preparation and the right conditions, breeding Pristella Tetras is quite achievable, even for beginners.

Gender Differences

Before you start, it’s essential to know how to distinguish between the male and female of the species. Male Pristellas are generally slimmer and have more elongated dorsal and anal fins. Females, on the other hand, tend to be more rounded, especially when carrying eggs and ready to spawn. These differences may be subtle, so take your time to observe your fish closely.

The Breeding Process

  1. Setup a Breeding Tank: Prepare a separate breeding tank of at least 10 gallons, with a sponge filter, heater, and subdued lighting. Use fine-leaved plants or a spawning mop as a place for the fish to lay their eggs.
  2. Condition the Breeders: Feed the potential breeding pair a high-quality, protein-rich diet, including live or frozen foods, to get them in optimal breeding condition and the female ready to spawn.
  3. Soften the Water: X-Ray Tetras prefer soft, slightly acidic water for breeding. Aim for a pH between 6.0 and 6.5 and a temperature around 80°F (27°C).
  4. Introduce the Breeders: Once the breeding pair is well-conditioned, place them in the breeding tank in the evening. Keep an eye on them to ensure they get along and exhibit courting behavior.
  5. Spawning: These species of tetra fish are egg layers and typically spawn in the early morning. The female will scatter her eggs among the plants or spawning mop, and the male will fertilize them. You may observe them engaging in a dance-like display during spawning.

Some Breeding Tips

  • Remove the Parents: After spawning is complete, remove the parents from the breeding tank to prevent them from eating the eggs.
  • Monitor the Eggs: The eggs should hatch within 24 to 36 hours. Keep the lighting dim and the water quality stable to ensure the eggs develop properly.
  • Fry Care: Once the fry become free-swimming, usually within 3 to 5 days, you can start feeding them with insect larvae, infusoria or commercially available fry food. As they grow, you can gradually introduce baby brine shrimp or finely crushed flake food.

Related Species

If you’re a fan of the unique look of X-RayTetras you might be interested in other tetra species that are subtle on hues but huge on shimmer and translucence. These features can add a fascinating dimension to your aquarium, creating a sense of intrigue and wonder.

  • Glass Bloodfin Tetra (Prionobrama filigera): Glass Bloodfin Tetras have a translucent body with a silvery sheen, which allows their internal organs to be visible. Their red-tipped fins add a beautiful contrast to their clear bodies, making them an interesting addition to a community aquarium.
  • Glass Tetra (Moenkhausia oligolepis): Glass Tetras, also known as Iridescent Tetras, have semi-transparent bodies with an iridescent sheen that shimmers under aquarium lighting. Their bodies can display a range of colors, including green, silver, and blue, making them an attractive choice for those seeking unique fish.
  • Diamond Tetra (Moenkhausia pittieri): Diamond Tetras have a shimmering, silvery sheen that resembles the sparkle of a diamond. While not as transparent as X-Ray Tetras, their iridescent scales reflect light in a mesmerizing way, making them a stunning addition to any aquarium.
  • Silvertip Tetra (Hasemania nana): Silvertip Tetras have a delicate, shimmering appearance, with a silver sheen that graces their body and fins. Their semi-transparent bodies give them a subtle, ethereal quality, making them an elegant addition to your home aquarium.
  • Silver Tetra (Ctenobrycon spilurus): Silver Tetras, native to the rivers of South America, are known for their translucent bodies adorned with a subtle, silvery sheen. This semi-transparent appearance allows them to blend seamlessly with their surroundings, while their iridescent scales add a touch of glamor.

By adding one or more of these related species to your aquarium, you can create a captivating display of shimmering, translucent, and transparent fish that will undoubtedly draw attention and admiration.

FAQs about Pristella Tetras

How many Pristella Tetras should be kept together?

Pristella maxillaris are schooling fish, meaning they prefer to be in groups. A group of at least six fish is recommended to help them feel secure and display their natural behavior. However, larger schools can create an even more impressive visual display and lead to a more vibrant community.

How do I acclimate X-Ray Tetras to a new aquarium?

To acclimate your Pristella Tetra fish, first, float the sealed bag containing the fish in your aquarium for 15 to 20 minutes to equalize the temperature. Next, gradually add small amounts of aquarium water to the bag over a period of 45 minutes to an hour, allowing the fish to adjust to the new water chemistry. Finally, gently release the fish into the tank using a net, avoiding the introduction of any water from the bag.

What is the growth rate of X-Ray Tetras?

They typically reach their adult size within 6 to 12 months, depending on factors such as water quality, diet, and overall health. To support their growth, it’s essential to provide them with a varied diet and maintain proper water conditions.

What is the breeding behavior of Pristella Tetras in the wild?

In their natural habitat, Pristella Tetras spawn in areas with dense vegetation, usually during the rainy season when the water is soft and slightly acidic. They typically scatter their eggs among plants, and the male fertilizes them. Once hatched, the fry will hide in the vegetation until they are large enough to swim freely.

Are X-Ray Tetras Right for Your Aquarium?

Ultimately, the decision to introduce or X-Ray Tetras, to your aquarium depends on your personal preferences and the specific needs of your tank. Their unique appearance, hardiness, and peaceful nature make them an attractive choice for both beginners and experienced aquarists alike.

Remember, the key to success with these fascinating fish lies in providing a suitable environment, compatible tank mates, and proper care. By following the guidelines outlined in this blog post, you’ll be well on your way to creating a thriving, beautiful aquarium where your Pristella Tetras can flourish.

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