The X-Ray fish, also known as the X-Ray Tetra, is a freshwater fish recognized for its transparent body. This unique characteristic allows a glimpse into its internal skeletal structure and organs, giving it its common name.
Identifying the X-Ray Fish
The X-Ray fish (Pristella maxillaris) is also known as the Pristella Tetra, Golden Pristella Tetra, and Water Goldfinch. This small fish reaches about 1.5 to 2 inches (4 to 5 cm) in length. Its most distinctive feature is its translucent body, which provides a view of its spine and internal organs, giving it an X-ray appearance due to a lack of pigment.
Beyond its transparent body, the X-Ray fish exhibits subtle coloration. Its fins, especially the dorsal and anal fins, display yellow, black, and white banding. The caudal (tail) fin can have a red tint. The body is slender and somewhat flattened, typical of many tetra species. As a member of the Characidae family, it shares characteristics with other tetras, including schooling behavior.
Natural Environment and Behavior
The X-Ray fish originates from the aquatic systems of South America, inhabiting the Amazon and Orinoco basins, and coastal rivers. They thrive in slow-moving rivers, clearwater streams, and blackwater environments. During the wet season, they migrate into flooded savannahs for spawning.
In its natural habitat, the X-Ray fish is a micropredator, feeding on small invertebrates like insects, worms, and planktonic animals. They are omnivorous, also consuming algae and plant matter. This peaceful species lives in large groups, exhibiting schooling behavior as a defense mechanism against predators.
X-Ray Fish in Home Aquariums
The X-Ray fish is a common choice for home aquariums due to its peaceful temperament and hardiness. They are suitable for both novice and experienced aquarists. X-Ray fish should be kept in groups of at least six, preferably ten or more, to facilitate their natural schooling behavior.
A minimum tank size of 10 to 15 gallons is recommended for a small group, with 20 gallons or larger beneficial for a healthy school. They adapt to a range of water parameters, with ideal temperatures between 72°F and 82°F (22°C to 28°C) and a pH range of 6.0 to 7.5. Regular filtration and water changes maintain water quality. A darker substrate, driftwood, or plants can mimic their natural environment.
X-Ray fish are omnivores and unfussy eaters in captivity. A varied diet including high-quality flake or pellet foods, supplemented with live or frozen foods, is recommended. They are compatible with other peaceful, similarly sized community fish like small tetras, rasboras, guppies, mollies, and Corydoras catfish. Avoid aggressive or larger tank mates to prevent stress or predation.