The most famous Cryptocoryne is the Wendtii brown variety. This species has beautiful shovel-shaped leaves and grows very easily. This Wendtii is great for starter aquarium, but will also thrive in Cichlid Aquarium due to its robust nature.
Understanding Crypt melt - all Cryptocoryne species require stable water parameters and light conditions. Once planted, Crypts should not be moved otherwise it can trigger what is called Crypt melt. If a Crypt has a significant change of environment (ph, kh, gh, lighting intensity or duration, root disturbance etc), Crypt melt can be triggered. The leaves start to disintegrate as the plant prepares for its new environment - DO NOT WORRY! Your plant will begin to grow back over the next 30 days (sometimes sooner, sometimes later) - it's still very much alive and busy getting ready for the growth of new leaves. In the meantime, any decaying leaves should be trimmed and recycled in a compost bin.