The rummy-nose tetra (Hemigrammus rhodostomus) is a species of tropical freshwater characin fish originating in South America, popular among fishkeepers as an aquarium fish. One of many small tetras belonging to the same genus, it is on average 5 cm (2 in) long when fully grown, and is a long established favourite among tropical fishkeepers. The fish is one of several very similar species including Hemigrammus bleheri, and Petitella georgiae, and it is possible that more recently collected specimens available in the aquarium trade are members of one or other of these similar species. The common name applied to most of these fishes is "rummy-nose tetra", though other common names are in circulation (such as "firehead tetra" for H. bleheri, according to FishBase).