X-ray Tetra

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Species group:

Other common names: Red Belly X-ray Tetra; Goldfinch Tetra; Pristella Tetra; Signal Tetra

Scientific name: Pristella maxillaris

The basics:
The X-ray Tetra is a small member of the Characin family of fish which is native to heavily vegetated clearwater streams in northern South America. It is a schooling fish and feeds on insects and zooplankton.

The X-ray Tetra gets its name from its characteristic transparent appearance. Although the spine of this fish is clearly visible, other internal organs are sheathed in a silver colored sac. The dorsal fin has a black band across its middle. This black band is bounded by a white band above and a yellow band below. The caudal fin is edged with orange. A new variety of Pristella maxillaris, the Red Belly X-ray Tetra, has a striking appearance, and is becoming a popular choice for Tetra lovers.

0-2 inches

The X-ray tetra is a shoaling fish and is kept in a tank in groups of at least 6 fish. They are peaceful by nature and thrive when kept in a community aquarium. Avoid keeping them with fish that are larger in size and display aggressive tendencies. This makes the Tetras timid and they will spend most of the time hiding from their larger tank mates.

Due to their small size, these fish require a tank with a minimum capacity of 10 gallons. In their natural surroundings, they reside in water bodies that are dimly lit. To mimic these conditions, some floating plants may be provided to minimize the amount of light that penetrates the tank. Pieces of driftwood and a few rocks may also be provided to serve as hiding places for the fish. For most of the day, the fish will swim about freely in the middle levels of the tank.

75.00-82.00 °F


40.000-180.000 mg/L


Easy fish, good tank mate, nice dances, transparent looking fish, good community fish


long tanks, pinkish intestines, different fin variations, transparency levels

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