Mystic Aquarium announced Monday that Chappy the seal has died.

The recently rescued gray seal pup was being treated for dehydration, malnutrition and pneumonia.

The aquarium said he had been responding well to treatment, but declined once again after he transitioned to eating whole fish.

Mystic noted that while unrelated to Chappy's immediate cause of death being intestinal issues, small pieces of plastic were also found in his stomach.

Chappy was rescued from the streets of New Haven on Feb. 16. Marine experts determined he was around 5 to 6 weeks old. 

The New Haven Police Department posted his story on social media – sparking interest in local communities. 

Police posted a poll soon after to name the beloved seal. The public landed on “Chappy” because he was found on Chapel Street.