X-ray tetra
Pristella maxima
beginner careOverview
The X-ray tetra (Pristella maxima), or Pristella tetra, is named for its translucent body — you can see its skeleton and the silvery capsule around its swim bladder through the skin. Fins tipped in yellow, black and white finish the look. Beyond its clear-glass novelty it’s a genuinely excellent beginner fish: exceptionally hardy, tolerant of a wide range of water conditions, and peaceful in a community. A settled shoal is lively and undemanding.
Tank & water
One of the most forgiving tetras, but still a shoaling fish:
- A cycled tank of at least 60 litres — cycle the aquarium before stocking and check how many fish in an aquarium.
- Temperature 22–28 °C with a reliable heater.
- Soft to hard water (pH 6.0–8.0) — their broad tolerance, including a little hardness, makes them very easy. Gentle to moderate filtration suits them.
- A planted layout — plants and a darker background make the translucent body and fin markings stand out.
Feeding
X-ray tetras are easy omnivores. A staple of quality tropical flake or micro-pellet, plus frozen or live daphnia, brine shrimp and bloodworm, keeps them healthy and their fin colour bright. Feed small amounts once or twice a day. See our fish food hub and best fish food picks.
Tankmates
Peaceful and adaptable, X-ray tetras are model community fish. Good companions include other small tetras like neon, glowlight and lemon tetras, corydoras, rasboras, peaceful gouramis and dwarf shrimp. Avoid large, aggressive or nippy species. Their toughness means they’ll happily join almost any calm mixed tank.
For a stable, planted community, our best aquarium for beginners and best nano aquarium guides are a good start — the X-ray tetra is one of the easiest and most distinctive first shoals available.
X-ray tetra — frequently asked questions
Are X-ray tetras good for beginners?
Very. The X-ray tetra (Pristella maxima) is one of the hardiest tetras, tolerating a wide range of pH and hardness and even slightly brackish water. In a cycled community tank with a shoal of six or more it's about as easy as tetras get.
Why is the X-ray tetra see-through?
Its body is naturally translucent, so you can see the backbone and the silvery swim-bladder capsule through the skin — hence the name. The yellow, black and white flashes on the fins add contrast against the clear body, especially in a group.
How many X-ray tetras should I keep together?
At least six, and eight or more is better. They're shoaling fish that are bolder, more active and better-coloured in a group. Kept in small numbers they tend to hide and lose the finnage display that makes them appealing.
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