That label, and the shape it describes, are almost all that remains of what was once a working feature of the coastal landscape south of Dublin city.

The pond appears on Barker's 'A Map of Old Merrion and Simmonscourt', surveyed in 1862 and held in the National Archives of Ireland (MSS. 211/2/2/2), where it is depicted as a D-shaped enclosure. One straight edge follows the shoreline itself, while a curving earthwork defines the landward boundary. This kind of tidal or shore-side fish pond, sometimes called a fish trap or fish weir, was a common enough feature of medieval and early modern estates; the enclosure would retain fish brought in on the tide, or simply hold live fish until they were needed for the table. The pond's position just south of Merrion Castle strongly suggests it was associated with that castle, functioning as part of the broader domestic economy of the estate. Merrion Castle itself was an important structure in the area, and a fish pond of this kind would have been a practical and valued asset, particularly given the religious requirement to eat fish on fasting days throughout the year.

The site today lies in an area that has changed considerably since the nineteenth century, with coastal development and land reclamation altering much of the shoreline south of Dublin Bay. The earthwork enclosure shown on Barker's map may no longer be legible on the ground, and the serpentine outline recorded on the Ordnance Survey maps has not survived in any obvious form. Anyone interested in tracing what remains would do well to consult both the historic OS six-inch sheets and the Barker map through the National Archives before visiting, using those documents to orientate themselves against the modern landscape. The record reference DU023-001005- holds the site's entry in the national monuments database, which can provide additional context for what to look for and where.