X-ray Tetra Pristella maxillaris

The X-ray Tetra is native to the Amazon and Orinoco basins and to the Guiana Shield. It can tolerate acidic, akaline or even mildly brackish waters.

Depending on the light and water clarity, the body can be translucent - hence its name - or silvery. Fins are yellow, black and white except the tail which is red on adults. There is also a gold albino form, above right.

The only species in its genus, they live in schools of 10 or more and can grow to 5cm long. They eat small insects that fall to the water from plants.