P. Clemenz & T. Steinemann (eds), 3000 Jahre Glaskunst von der Antike bis zum Jugendstil, exhibition cat. (Kunstmuseum Luzern), Lucerne, 1981, no. 437.
For a similar fish-shaped vessel, see Matheson, 1980, p. 87ff, no. 239. Matheson notes that while blown vessels in the shape of fish are known to have been produced in Cologne, those with trailed details such as eyes and fins are thought to have originated in the Eastern Mediterranean. The Yale example retains a gold link chain, which is joined to the fins and hangs beneath the body of the fish, with a circular ornament attachment suspended below. Matheson draws a parallel to a bronze fish in the Metropolitan Museum of Art, New York, which has a similar chain, and also a separate stopper, suspended on a second chain, which closes the mouth of the fish (acc. no. 62.10.4). Some of these glass fish-shaped flasks may have been used to contain garum, the strong fish sauce made from fermented salted entrails.