A keeper mentioned that the majority of the animals (including the rarities: Hummingbird, Arapaima and Widowbird) will be moving to the Orchideeënhoeve in Luttelgeest.
I've visited a few times before. It's a very nice butterfly garden (one of, if not the largest in the Netherlands) with multiple greenhouses, a nice collection of birds, and a wonderful flamingo aviary (with lemur islands)
I really hope they'll create a large aquarium, or add underwater viewing to a larger pond, for the new fish. Klein Costa Rica has an incredible collection of exotic fish, including Iridescent shark catfish, Giant gourami, Tanganyika tilapia, Multiple species of Amazonian rays and Silver arowana. As well as two Pig-nosed turtles.
De Orchideeënhoeve already has a group of Redtail catfish, that are held in a rather mediocre tank that isn't big enough to house all of the other species mentioned. They've had Arapaima before, though I can't say with certainty where they were held.