[2] Diapterus auratus has a rhomboidal, compressed body with the head showing a lower profile which is distinctively concave.

The colour is silvery to olive overall, slightly darker on the upperside,[3] and the spiny dorsal fin has a thin black edge.

[3] Diapterus auratus is a demersal fish which can be found in shallow coastal waters at depths sown to 10 metres (33 ft)[4] where is shows a strong association with lagoons and vegetated sand grounds, it is also a frequently encountered transient species in mangrove-lined creeks.

The largest numbers are found in areas where there is submerged vegetation and at locations more distant from the inlets of seawater into lagoons where there is lower salinity.

[1] The smaller fish, with a total length of less than 11.5 centimetres (4.5 in), feed mainly on plant material but will also eat nematodes, copepods, and ostracods.

[7] Diapterus auratus was first formally described in 1841 by the Italian priest and naturalist Camillo Ranzani (1775-1841) with the type locality being the seas around Brazil.