Taxonomy
The genus, Nannostomus, was first erected by Günther in 1872 with the type species, Nannostomus beckfordi. In 1876, Steindachner described three more species, Nannostomus unifasciatus, Nannostomus eques (pictured below) and Nannostomus trifasciatus (pictured above). In 1909 Carl H. Eigenmann described Nannostomus marginatus, Nannostomus minimus and Nannostomus harrisoni. All but N. minimus have been popular with aquarists since the early twentieth century, in part due to enthusiastic articles written about them, and compelling photographs taken of them, by William T. Innes that were published as early as 1933. Over the years, the genus was split by subsequent authors into other genera including Poecilobrycon and Nannobrycon. After nearly a century of debate on the subject, Dr. Stanley H. Weitzman and Dr. J. Stanley Cobb restored earlier taxonomy and expanded upon it, unifying all species under Nannostomus in 1975. This comprehensive revision of the genus has now been widely accepted. Dr. Weitzman is also responsible for the description of five of the more recently introduced species, Nannostomus marilynae, Nannostomus limatus, Nannostomus nitidus, Nannostomus britskii and Nannostomus anduzei. Eighteen species are now known to science, most of which are also known to aquarists. Several other unidentified Nannostomus have been imported over the years, many found as by-catch with other small characins, but their taxonomic status is yet to be determined.
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