Lioconcha castrensis, common name the zigzag venus, is a species of saltwater clam, a marine bivalve mollusc in the family Veneridae, the venus clams.
The shell of Lioconcha castrensis reaches a maximum length of about 55 mm; it is the largest species in the genus Lioconcha. The shape of the shell is trigonal ovate, with a subtruncated posterior margin and a rounded ventral and anterior margin. This species is equivalve. The valves are quite thick and show fine wrinkled growth lines. This species has a wide range of variations. Usually the shell has blue-black to tan zigzag lines and chestnut-brown blotches on a generally white background. The interior is white.
This species has a wide Indo-West Pacific distribution.