Thailand has fallen in love with Moo Deng, but the Khao Kheow Open Zoo in Chon Buri says visitors need to behave around the two-month-old pygmy hippopotamus.
Zoo staff made the request on Thursday after videos circulated on social media showed some visitors throwing what looked like shellfish at the new star of the zoo while she napped.
Zoo director Narongwit Chodchoi released a statement asking visitors not to throw objects at the young animal due to the risk of injury.
Another clip shows a visitor reaching over and splashing water on Moo Deng, angering many netizens.
Mr Narongwit also said the best time to visit Moo Deng is when she is awake.
He said the zoo has installed CCTV cameras around the enclosures. If visitors do not cooperate, the zoo may consider legal action to protect its wards, he said.