There are 3 species of small tetra that share the common name Rummynose (Rummy Nose, Rummy-nose) Tetra. The one above is further clarified as the Common or Brilliant Rummynose and can be distinguished by the red colour extending a little from the head as if bleeding in a line well beyond the gill. It is native to the Rio Negro and Rio Meta basins in northeast South America.

Another species in the same genus, clarified as the True Rummynose, H. rhodostomus, looks like the image above left, with the red limited only to the head and with a faint black line from the caudal fin to half way along the flank. It is unclear whether that shown is indeed the True Rummynose since it was with a group of mixed (hybrid?) Hemigrammus. Its native range is also northeast S. America, but in the Orinoco and lower Amazon basins in Venezuela and Brazil. All are about 5cm (2 inches) long and are said to use their stripey tails to communicate to each other.

The third species called Rummynose is a separate genus and is clarified as the False Rummynose. Those above, believed to be False Rummynose, ironically are the only ones to show a "rummy" (red) nose as opposed to full red head. The False Rummynose can have a full red head but does not have the "bleed" beyond the gills of the Common Rummy and has the black half line on the rear flank of the True Rummy. However, it does not have the lower black spot on the caudal peduncle (wrist of tail). It is native to the upper Amazon in Peru and the Rio Purus, Negro and Madeira basins.