The dolphin was first spotted just before 11 a.m. Thursday near Cropsey Avenue and Bay 54th Street.
Around 2:30, the dolphin appeared to try to beach itself on rocks, and then drifted slowly in the water and has not been seen since.
Humans were not the only ones getting out and enjoying the weather in New York Monday – the dolphins were out and about too.
“The dolphin was diving and swimming normally and there were no observable injuries noted,” The Riverhead Foundation for Marine Research and Preservation wrote on its Facebook page.
The male dolphin was hampered by kidney stones, gastric ulcers and parasites, according to Kimberly Durham of the Riverhead Foundation for Marine Research and Preservation.
The wayward dolphin that lost its way, ended up in the polluted Gowanus Canal and died was undergoing a postmortem exam Sunday.
The wayward animal stopped moving shortly after 5:30 p.m. after getting wedged between a rock and a pillar below the Union Street Bridge.
The 5-foot female dolphin was found around 9:30 a.m. Friday, but died several hours later.
The animal was found floating near Pier 59 in the morning — days after a dolphin was spotted swimming in the Hudson.
An officer and a volunteer had poured buckets of water on the stranded dolphin in a failed effort to keep it alive.