The four-month-old male had colobomoa, a serious eye condition which causes vision problems and severe pain.
A statement on the park’s Facebook page said: “While surgery can help to relieve pain in some cases, the seriousness of his condition meant we needed to take this incredibly difficult decision following veterinary advice to ensure he did not suffer.
“We are continuing to monitor our two female cubs, who also have this eye defect though not to the same degree at this time. Our thoughts are with everyone who works with the cubs.”
The cubs were born in August.