Pristella Tetra (X-Ray): Care, Diet, Tank Mates & More!

The pristella tetra (aka x-ray tetra) are an under-appreciated freshwater species that has a lot to offer. This fish is known for being low-maintenance, beautiful, and fun to observe.

They’re also great fish for community tanks, meaning you can usually find a place for them in your aquarium if you have enough space.

This guide goes over everything you need to know about pristella tetra care. You’ll learn about their ideal tank setup, diet, lifespan, tank mates and more!

Species Summary

Native to the coastal rivers of South America, the pristella tetra (Pristella maxillaris) is a beautiful tropical fish with a surprisingly hardy lifestyle. This freshwater fish migrates throughout the year, moving with the changing environment and seasonal floods. For this reason, it’s highly adaptable to life in captivity.

One pristella tetra

The pristella tetra is part of the characidae family. Interestingly enough, it’s the only member of the pristella genus.

In the wild, you can find these fish in Brazil, Guyana, Orinoco, and Venezuela. However, most of the specimens you see for sale are commercially bred. Peaceful, low-maintenance, and resilient, pristella tetras make an excellent choice for new and seasoned aquarists alike.

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There’s no way to mistake pristella tetras for another species. These fish are distinct and have several features that make them stand out.

The fish’s main body is silvery and nearly transparent. They still have some identifiable color and sheen, but they’re clear enough to see their organs as they swim. You might see the fish marketed as the x-ray tetra or x-ray pristella tetra thanks to this unique trait.

Beyond the see-through body, the most stand-out feature is the coloration on the fins! The dorsal and anal fins feature three stripes of vibrant yellow, staunch black, and crisp white. The yellow stripe is closest to the body, while the black one is in the middle.

In addition to the eye-catching stripes, pristella tetras have red or pinkish tailfins. The intensity of the red varies from one fish to the next. You might also see a tinge of yellow at the caudal fork.

Author Note: Pristella tetras are deep-bodied tetras. They have some girth around the midsection. Generally, females are stockier than males. You can also see their eggs develop when they spawn, making it easy to distinguish between the sexes.


With the proper diet and top-notch living conditions, you can expect the typical lifespan of a pristella tetra to be between four to five years.

There are no ways to precisely determine a fish’s life expectancy. Far too many factors come into play.

Author Note: As always though, good care can make a big difference. This will result in stress-free living, which makes the fish less susceptible to serious health problems. Also, purchasing your pristella tetra from a trustworthy seller can improve your chances as well.

Average Size

Like many other species in the tetra family, pristella tetras are small. The average size of adults can reach lengths of about two inches at most. Many fish won’t even get to the upper end of the size spectrum, staying closer to 1.75 inches when fully grown.

Thanks to their small size, these fish work well in moderately sized tanks (some even use them as nano fish). They prefer to stay in groups, allowing you to keep a nice shoal for a beautiful display.

Pristella Tetra Care

Pristella tetra care is very straightforward (as long as you understand their core needs). They’re built to withstand changing conditions, making them a hardy and resilient tank inhabitant.

As always, there are some established guidelines you need to follow if you want these freshwater fish to thrive. Here are some essential tips you don’t want to miss!

Tank Size

A small group of pristella tetras needs a tank size of at least 10 gallons to stay healthy. However, we recommend bumping that minimum up to 15 to 20 gallons if possible.

Pristella tetras are active schooling fish. They tend to stick together and explore their environment as one larger unit. While they might be small individually, you have to accommodate a group of at least six (more on that later).

Author Note: Because of this, extra room is always preferred. These freshwater fish are playful and active. Providing more room to roam can help keep them stress-free and happy. Plus, a larger tank can make managing the bioload much easier.

Water Parameters

In the wild, these fish live exciting lives. Unlike most tetras, x-ray tetras can handle somewhat brackish waters. They come from coastal rivers that aren’t entirely freshwater.

Pristella maxillaris swimming in a freshwater aquarium

That said, you don’t have to worry about salinity in a closed freshwater tank. During the rainy season, these fish move inland to waters with virtually no salinity. They migrate to flooded savannahs, which are filled with dissolved minerals, decaying plants, and more.

For this reason, water hardness is not a critical factor like it would be with most fish. Pristella tetras thrive in a broad range of conditions. The key is to stick within the accepted parameters and avoid sudden fluctuations.

  • Water temperature: 64°F to 82°F (aim for around 75 degrees)
  • pH levels: 5.8 to 8.5 (Between 6.0 to 7.5 is ideal)
  • Water hardness: 4 to 8 KH

Author Note: Make sure you invest in a reliable and accurate water test kit for your aquarium. That will make it easy to check in on the water conditions and make any necessary adjustments before the health of your x-ray tetra is negatively affected.

Decorating The Inside Of Their Tank

Pristella tetras might be used to an ever-changing environment in the wild, but a standard tropical biotope is suitable for captivity.

This means one of the most important aspects of pristella tetra care is recreating the habitat of their native rivers. That means adding tons of plants, driftwood, rock caves, and more.

Start with a layer of a sand substrate. Spread it evenly and use it to anchor some live or silk plants. Live plants are always best, as they can improve water conditions. Utilize a variety of species like Java fern, Amazon swords, and more.

You can also add some Indian almond leaves to the tank’s bottom to improve pH and infuse some natural tannins into the water.

Author Note: Use natural-looking decor to create plenty of hiding spaces for these fish. You want to keep much of the center empty so that they have room to explore and swim, but little pockets of shelter are good to give the fish solace when they feel stressed or overwhelmed.

Common Possible Diseases

You wouldn’t know it from looking at them, but pristella tetras are surprisingly resilient against disease. They’re not particularly sensitive like other common types of tetras.

That said, no freshwater fish is immune to disease altogether! X-ray tetras can suffer from all the usual ailments.

Skin flukes, parasitic infections, and bacterial diseases are all possible. These health issues can plague fish of all ages. Some conditions, such as Ich, are highly contagious and potentially lethal.

If you spot any trouble, make sure to quarantine sick fish as quickly as possible. The good news is that many of the common health problems are easy to treat with over-the-counter medications.

Most diseases are actually avoidable as well. Monitor tank conditions regularly and do your part to create a healthy environment. This includes cleaning messes and performing 25-percent water changes every two weeks!

Food & Diet

Pristella tetras aren’t picky about their food either. They are tried and true omnivores that will eat just about anything you provide!

It’s best to make commercial flakes or pellets their dietary mainstay. Go for premium foods with balanced nutrition.

Every once in a while, you can also provide high-protein snacks. X-ray tetras often seek out insect larvae and small bugs they find on the surface in the wild. High-protein snacks are like finding that elusive treat in their natural habitat!

You can provide some freshly hatched brine shrimp. Freeze-dried or frozen goods work, too. Try offering up bloodworms and other similar foods.

Author Note: Pristella tetras like to eat several times a day. Most aquarists will feed them two or three times. For each feeding, provide only enough food that the group can eat in three minutes to avoid ruining tank conditions.

Behavior & Temperament

These eye-catching fish are peaceful and easy-going, making this one of the easiest parts of pristella tetra care. Aggressive behavior is not something you have to worry about. A bit of infighting here and there is normal, but it rarely turns into something serious.

Two x-ray tetras

Pristella tetras are peaceful to each other and other like-minded creatures in the tank!

That said, this species is easy to scare. It doesn’t take much to spook the fish, so make sure that there are plenty of hiding spaces to give them some peace in those moments.

As mentioned earlier, x-ray tetras are schooling fish. They must stay in a group of at least six. If possible, keep them in a bigger group!

When kept in small groups or alone, these fish can become even more skittish than they already are. Solitary fish will spend most of their time in hiding and will usually succumb to stress-related health issues.

Tank Mates

Beyond fish of the same species, pristella tetras can get along well with many other freshwater tank inhabitants. As a peaceful species, you must ensure that any tank mates you add to the community have a similar temperament.

These fish will not survive in the presence of aggressive or even semi-aggressive species. Their easy-going nature makes them a prime target for known aggressors like cichlids.

It’s best to steer clear of larger fish as well. Even peaceful giants may mistake them for food. Keep community fish to roughly the same size.

Some good tank mates for the pristella tetras include:


Pristella tetras willingly breed in captivity. In their natural habitat, these fish migrate to the flooded savannahs to breed among plants. Fortunately, recreating those migratory conditions isn’t too tricky with a separate breeding tank.

The breeding tank should hold at least ten gallons. Keep the temperature around 78 degrees Fahrenheit and the pH balance to near-neutral. Add fine-leaf plants to give the eggs and fry a place to hide. Make sure to cover any filter inlets with sponges as well.

Now comes the hard part. X-ray tetras can be a little picky about spawning partners. You can breed the fish in larger pairs. But for the sake of egg survival, it’s best to do so in pairs.

Place a pair into the breeding tank and condition them with protein-rich foods. If the female doesn’t swell with eggs within a couple of days, remove the team and try a different combination.

Eventually, you’ll find a suitable pair, and the female will lay 300 to 400 eggs. Remove the adults immediately after she lays her eggs. The adults will quickly consume the eggs that plants don’t hide.

The eggs will hatch in 24 to 36 hours. In another three to four days, the baby fry can swim freely on their own. At this point, provide fine powdered foods or infusoria. Once they’re big enough, you can move onto baby brine shrimp or infusoria.

Closing Thoughts

Pristella tetra care isn’t something you should be worried about. These fish are very beginner-friendly and are a fantastic option for any owner who doesn’t want a lot of hassle.

With their gorgeous looks and low-maintenance nature, this is a freshwater species that we highly recommend. In fact, we think they should be a lot more popular than they are!

We hope you found this guide helpful and feel prepared to jump into x-ray tetra ownership. If you still have questions that weren’t covered in this guide, don’t hesitate to ask us!

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