What significant grouping does the Order Characiformes unite X-Ray Tetra with?

Piranhas and many other South American tetras

The placement of *Pristella maxillaris* within the Order Characiformes is significant because this grouping unites the X-Ray Tetra with several other well-known aquarium species, most notably including piranhas and numerous other varieties of South American tetras. Recognizing this shared order provides valuable insight for aquarists, suggesting underlying biological predispositions related to their native environment, which typically involves softer, slightly acidic water conditions common to South American habitats. Furthermore, this grouping often suggests a propensity for schooling behavior among the members of Characiformes, prompting owners to ensure appropriate social structures are maintained for optimal well-being, even if specific dietary needs diverge widely between different members of the order.