The Waikiki Aquarium announced today that its beloved giant clam, or Tridacna gigas, died of suspected natural causes on Tuesday. The clam was believed to be the oldest of its species in captivity worldwide. It was more than 40 years old.

The aquarium acquired the giant clam from a clam farm in Palau about 30 years ago. The clam resided in the aquarium’s Barrier Reef exhibit, where it grew to over 200 pounds, and quickly became a guest favorite.

Giant clams are the largest living marine bivalves, according to the National Oceanic and Atmospheric Administration, and typically inhabit tropical coral reefs in coastal regions throughout the Indo-Pacific Ocean.

Currently, seven giant clam species, including the Tridacna gigas, are candidate species for listing under the Endangered Species Act due to threats that include climate change, disease and poaching, NOAA said.

“Needless to say, we are all saddened at the demise of one of our flagship, and oldest, animals,” said Andrew Rossiter, Director of the Waikiki Aquarium, in a statement. “The clam looked fine over the weekend, but showed a catastrophic decline on Monday, when it began releasing clouds of eggs into the exhibit.”

He added, “Unfortunately, despite the close attention of our staff, there is little that can be done when a clam falls ill. We have checked the parameters in the exhibit, and they have remained unchanged for at least the past year.”

Rossiter said the aquarium has sent tissue samples to a lab for further analysis.

“However, Biology 101 tells us that the older the animal, the more-likely it is to die, and I expect its demise will be attributed to natural causes,” he said.