Mimagoniates is a genus of small tetras from the Atlantic Forest region and the Paraná-Paraguay basin, with atlas records from Brazil, Argentina, and Paraguay. They belong to the glandulocaudine group of characins, tetras built around elaborate courtship structures on the male's fins, and Mimagoniates carries the group's signature trait right into its common names — every one of the atlas's seven species is called some form of "croaking tetra," for the audible clicking or croaking sound males make while courting females, a genuinely unusual behavior among freshwater fish. At 1–2.5 in, they are slender, often blue-flanked schooling fish typical of shaded forest streams.
Species such as the blue croaking tetra (M. lateralis) and the beautiful croaking tetra (M. pulcher) do reach specialist aquarium circles, valued for their subtle iridescent blue coloring and that unusual courtship sound, though they stay a niche interest rather than a mainstream import. Conservation data are thin across the genus — four of the seven atlas species are Not Evaluated and two more are Near Threatened, with only one ranked Least Concern — a pattern consistent with the heavy habitat pressure on Atlantic Forest streams, even though formal assessments haven't caught up with most of the genus yet.