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Contents
Overview
The X-ray tetra, or pristella tetra, earns its name from a body so translucent you can make out its spine and swim bladder. Against that see-through body, the dorsal and anal fins carry a striking yellow, black and white pattern, set off by a reddish tail. Golden and albino varieties are also sold.
It lives in rivers and flooded areas across northern South America, from the Orinoco through the Guianas to the lower Amazon, where it copes with widely varying water, even slightly brackish conditions. That adaptability makes it one of the easiest and most rewarding tetras for beginners: peaceful, active, undemanding about water and eye-catching in a school.
Care and tank setup
A school of eight does well in 16 gallons (60 L) or more, ideally a tank about 24-30 inches (60-75 cm) wide that is fully cycled, with a filter and heater.
- Decor: mix dense plant thickets with open swimming lanes. A dark background and slightly subdued lighting bring out the fin markings, which almost disappear under harsh light over pale gravel.
- Water: one of the least fussy tetras, it handles average tap water well. Weekly 20-30% water changes and stable conditions are all it needs.
- Tank mates: great with other tetras, rasboras, peaceful livebearers, corydoras, shrimp and dwarf cichlids. Avoid large or boisterous fish.
It cruises the middle of the tank in loose groups that tighten into a compact school when startled. With fewer than six it turns shy and loses much of its charm.
Feeding
An easygoing omnivore. It eats fine flakes, micro pellets and freeze-dried foods, and relishes small live or frozen fare such as brine shrimp, daphnia or chopped bloodworms. Offer one or two feedings a day of what it can finish in a couple of minutes, and rotate foods to keep the fin colors strong.
Breeding
An egg scatterer that drops its eggs among fine-leaved plants and does not guard them. Pairing can be trickier than with other tetras because individuals seem choosy about mates, but several well-conditioned adults in a breeding tank with soft water, dim light and moss will usually spawn. Remove the parents right afterward. The fry live on infusoria for the first few days.
Compatible tank mates
Species from our database that share water parameters, size and temperament with the X-ray tetra. Calculated from the data in each profile.
Bristlenose pleco Ancistrus sp. 26 gal (100 L) · 72–81 °F (22–27 °C) 
Betta fish Betta splendens 7 gal (25 L) · 75–82 °F (24–28 °C) 
Bronze cory Corydoras aeneus 21 gal (80 L) · 72–81 °F (22–27 °C) 
Guppy Poecilia reticulata 14 gal (54 L) · 72–82 °F (22–28 °C) 
Cherry barb Puntius titteya 16 gal (60 L) · 73–81 °F (23–27 °C) 
Tiger barb Puntigrus tetrazona 26 gal (100 L) · 72–79 °F (22–26 °C) 
Nerite snail Neritina natalensis 5 gal (20 L) · 72–82 °F (22–28 °C) 
Horned nerite snail Clithon corona 5 gal (20 L) · 72–82 °F (22–28 °C) 
Amano shrimp Caridina multidentata 11 gal (40 L) · 64–82 °F (18–28 °C) 
Cherry shrimp Neocaridina davidi 5 gal (20 L) · 64–81 °F (18–27 °C) 
Dwarf gourami Trichogaster lalius 16 gal (60 L) · 75–82 °F (24–28 °C) 
Otocinclus catfish Otocinclus vestitus 16 gal (60 L) · 70–79 °F (21–26 °C) Check the compatibility of your whole tank →
What not to keep it with
Popular species you shouldn’t house with the X-ray tetra, and why.
- Common goldfish: incompatible temperatures, one may eat the other due to size
- Angelfish: one may eat the other due to size
- Clown loach: one may eat the other due to size
- Oranda goldfish: incompatible temperatures, one may eat the other due to size
- Oscar: one may eat the other due to size, incompatible temperaments
Recommended equipment
What you need to keep the X-ray tetra healthy, checked against Amazon stock.
Frequently asked questions
How many liters does a X-ray tetra need?
At least about 60 liters for a group of at least 8 fish. More space always helps keep the water stable.
What water temperature does the X-ray tetra need?
Between 24 and 28 °C, with a pH of 6 to 7.5.
What fish can live with the X-ray tetra?
Based on water, size and temperament, it fits with species such as Bristlenose pleco, Betta fish, Bronze cory, Guppy and Cherry barb. Use our compatibility calculator to check your whole tank.
Can the X-ray tetra be kept with shrimp?
Yes: it usually won’t eat adult shrimp, though some shrimplets may get picked off. A tank with plenty of moss gives the babies cover.
