Cryptocoryne affinis can usually be recognised by its bullated leaves, although this trait might not be very evident in immersed plants. The lance-shaped leaves can reach a length of about a foot and typically have a pale midrib that is useful for identifying the species. As with most crypts, coloration is variable, but often the upper surface is glossy green while the underside is deep reddish purple. The inflorescence, which is rarely observed, is a tall and narrow spathe that ends in a tightly-spiralled limb.

Endemic to pristine rivers in Peninsula Malaysia, Cryptocoryne affinis is one of the oldest members of the genus to enter the aquarium hobby. The plant's popularity may stem from its tolerance of the hard, somewhat alkaline waters prevalent in the homes of European hobbyists, although it is also found in acidic blackwater habitats. Long noted for its tendency to melt when growing conditions change, the plant should therefore not be disturbed after its introduction to a setup. Some patience is required before it establishes itself, after which it is reported to be a rapid propagator via spreading rhizomes. A slightly shaded position and good water flow may also aid the development of more robust leaves.