A conchylia cup is an Ancient Roman glass cup type with a conical base and a slightly everted rim, made of transparent to slightly colored glass.
Its distinguishing characteristics are stylized open mouthed fish with indented fins and curving tails, often made of translucent glass and applied wavy colored threads, and affixed to the outer surface of the cup to produce its three-dimensional aspect.
Fish appliqués have been found throughout the Mediterranean, and provide no good clues for provenance.
These cups were possibly used either as oil lamps, drinking vessels or for holding garum sauce.
The only cup stemming from a datable context is from Cologne, and dated to the fourth century AD.