The Aquarium of the Pacific's three-month-old Magellanic penguin chick was recently euthanized due to an unknown severe condition. Photo by Robin Riggs, courtesy Aquarium of the Pacific.

The Aquarium of the Pacific announced Tuesday the death of its three-month-old female Magellanic penguin chick, which was euthanized Aug. 29 due to an unknown condition it developed several weeks after it was born and wouldn’t foreseeably survive.

“The chick’s condition had recently worsened despite all efforts, and it was determined that euthanasia was the most humane choice,” aquarium officials said in a statement. “This was a painful decision that was not made lightly. The penguin chick, which was hatched in late May, is beloved by the staff and will be greatly missed.”

The aquarium’s chick, which was not named before its death, was the first Magellanic penguin to hatch this year as part of the aquarium’s annual breeding program.

The young baby Magellanic penguin that was recently hatched at the Aquarium of the Pacific. Photo by Robin Riggs, courtesy the Aquarium of the Pacific.

The penguin was born to parents Robbie and Kate who, the aquarium said, had been paired together for the first time this year. But during the first few weeks the hatchling was nesting with its parents, aquarium staff noticed she had lost weight and was lethargic.

The chick was moved into critical care for two months and treated for what staff initially believed was pneumonia, which was resolved before a new condition emerged.

Aquarium officials said they have not yet diagnosed the penguin’s condition.

“The white blood cell count was extremely elevated at times,” said Rob Mortensen, the aquarium’s Assistant Curator of Mammals and Birds. “We’ve sent away tissues for samples so hopefully that will tell us more.”

Mortensen also noted that the penguin had developed hip dysplasia, although it’s unclear if the condition was genetic or the cause of an infection.

During the months the chick was in critical care, the she was cared for by a team of six working around the clock, Mortensen said.

“We had staff coming and going during the night to assist feeding, medicate and give fluids,” he explained. “They were really attached.”

Any year there is a medical-related situation, the aquarium does a review with its veterinarian team before proceeding with the breeding program the next year.

“That’s a normal part of our process,” Mortensen said. “We’ll try and take some lessons that we’ve learned but hopefully we won’t have to experience this again. We certainly gained experience in how to take care of a chick that needed a lot of care. A lot of our staff hadn’t had that yet.”