It is somewhat understudied and lacks a conservation status, but it is present in a region that is the subject of an ecological restoration project - the Jequitinhonha River.

Other factors, such as a lateral stripe and horizontal humeral spot, are shared with other Astyanax species, but aspects of dentition and fin structure can be used to differentiate.

)[5] The original description of A. brevirhinus was somewhat brief, but it received a more detailed update from Eigenmann in the 1921 volume of "The American Characidae", a series of articles published in the journal Memoirs of the Museum of Comparative Zoology at Harvard College and later compiled into a book.

The reason for this allusion, while not articulated in the nominal text, is thought to refer to the type species Astyanax argentatus, which has large, silvery scales, like armor or a shield.

Astyanax brevirhinus reaches a maximum of roughly 10.0 cm (3.9 in) TL (total length, with the tail fin included).

[6] When in distress, such as during laboratory transport or in conditions perceived as threatening, individuals of A. brevirhinus may slightly darken in color.

[13] Observation in laboratory conditions reveals shoaling behavior amongst conspecifics of A. brevirhinus, not uncommon in species of Astyanax (both captive and wild).

[1] Previous diamond mining activity in the Jequitinhonha River region has been met with an ongoing preservation project in hopes of restoring local flora and fauna diversity, but the prognosis is not entirely positive; the riparian zone has been deemed unlikely to return to its former health.

However, efforts have not been entirely without payoff, and the riparian zone has had some recovery in the past 7 to 11 years, which means that aquatic species like A. brevirhinus are likely to retain the associated benefits if the trend continues.