Though not all: A long block south of the Cortelyou cod I found the Ditmas dolphin. These plaques decorate Ocean Parkway, whose construction began in 1874 to a design by Frederick Law Olmsted and Calvert Vaux; its bicycle path, the country's oldest, was completed two decades later.
The aquatically themed plaques also reportedly include the Avenue C clam and 18th Ave. anchovies (edible), the Lawrence leatherback (protected) and Webster whale (should be), plus the Parkville puffer and Newkirk needlefish (meant for each other, like the shlimazl and shlemiel).
Marine-life plaques on Ocean Parkway
Cod, at Cortelyou Rd., and dolphin, at Ditmas Ave., Kensington, Brooklyn; other wildlife to the north and south