Common Sergeant

Is this a wild butterfly or is there a butterfly house at the zoo?

@DavidBrown a small butterfly aviary opened in May this year, housing mostly native species. The specie in the photo is native and can be seen both in the aviary and wild on Zoo grounds.

Fragile Forest - Butterfly Aviary | ZooChat

This photo was take in the Butterfly aviary, but according to a website, this species is no longer found in Singapore (but is still present on the Peninsula).

@Hix thanks, you're right. My bad, there are other species of "sergeant" butterflies still found in Singapore, but the Common Sergeant may be extinct here. The Butterfly Circle is a useful resource:

Butterflies of Singapore: Sergeants of Singapore