X-ray tetra

Care at a glance

Overview

Keep a school of at least six to settle them and reduce nipping. They are active swimmers that stay mostly in the middle of the tank. They are not fussy eaters, taking flake, micro pellets, and frozen foods like bloodworms and brine shrimp. Around 70 liters suits a group, and a planted tank with some open water shows them off and keeps them comfortable.

In the wild

The X-ray tetra lives in coastal rivers and streams across Venezuela and the Guianas, including waters that turn brackish near the sea. That tolerance for a range of conditions makes it adaptable in the tank. Soft to moderately hard water with a pH from about 6 to 8 works, kept in the mid 20s C, with some plants and open swimming space.

Good to know

It is a small characin in the family Characidae, reaching about 4.5 cm. The body is see-through, so you can make out the backbone and the swim bladder, which is where the name comes from. It is an egg scatterer with no parental care, and spawning it is on the harder side. Unusually for a tetra, it handles slightly brackish water, reflecting its coastal range.

Did you know

Its standout feature is built-in armor against sound rather than just the clear body. X-ray tetras have a chain of small bones, the Weberian apparatus, linking the swim bladder to the inner ear. This gives them sharp hearing and helps the whole school react together to nearby movement or noise.

Related species

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  Serpae tetra

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