This freshwater ray has small eyes and a disc shaped roughly like a lily pad (the snout is slightly concave).^[3] It is brownish above with a dark vermiculated or reticulated pattern.^[3] It reaches up to 1.6 m (5.2 ft) in disc width and 110 kg (240 lb) in weight, making it one of the largest species in the family.^[3] There are unconfirmed claims of much larger individuals, but these are considered highly questionable.^[4] Most individuals do not surpass a disc width of 1.3 m (4.3 ft).^[3] Males reach maturity at a disc width of about 60 cm (2.0 ft) and females at about 72 cm (2.4 ft).

It mainly feeds on fish,^[5] but also take invertebrates such as insects and crustaceans,^[3] and it is a top predator in its habitat.^[6] Adults are found in relatively deep waters in main river channels, but move to shallower waters to feed at night. After a nine-month gestation, the female give birth to an average of two young with a disc width of about 16 cm (6.3 in). Juveniles are found in relatively shallow waters at sandy beaches and in creeks.^[3]