This swortplant hybrid got known already in the 1980s under trading names such as "Echinodorus osiris Double Red". It was described as a species and named in honor of the plant breeder Hans Barth sen. (Dessau, Germany), but later it turned out as a hybrid that probably arose in the facility of an Australian breeder. Echinodorus × barthii is also traded as "Echinodorus rubra". Its submerged leaves are narrowly elliptic, slightly rolled downwards and deeply dark red coloured. The longitudinal ribs are light green, contrasting with the surrounding leaf area. The submerged leaf rosette gets broader than high; it is only 10-20 cm high but 20-40 cm broad. As well as other Echinodorus, it is mostly delivered in its emersed form, having longer stalked, rather green leaves. Planted into the aquarium, new colourful submerged leaves will appear.
Echinodorus × barthii is an easy aquarium plant that also tolerates hard water. However it benefits much from a nutrient-rich substrate, as other Echinodorus. The optimum temperatures lie between 18 and 26 °C. A free, well lit place is recommendable.
Barth's Sword plant looks best as solitary plant in the midground and contrasts well with light green plants.