I agree that it looks like a tree or shrub of some sort but have no clue to what type. Nice though. Is someone keeping this in a vivarium? Looks like it needs to be in a dryer enviroment than a dart tank.
I don't have a species name for you, but from the picture it apears to be a member of the Rosaceae (Rose family) or one of the small closely related families. I assume that it is a shrub. Do you have a picture of mature foliage or fruit? Also do you know where it comes from. I know you said it is being grown in Singapore, but is it native to SE Asia? Is grown under tropical or temperate conditions? Is it an epiphyte?
Lots of questions. If you have the answers I may be able to come up with a name for it.