The ruby tetra (Axelrodia riesei) is a species of freshwater fish in the family Characidae.It is endemic to the Río Meta, Colombia, South America. In nature, it has a natural red colour, but this is somewhat lessened in captivity. Ruby tetras grow up to 3cm (01inches) to 3.5cm (01.4inches) long.
Named in honor of tropical-fish exporter William Riese, who collected the type specimen.[1]