Gardens by the Bay is a futuristic botanic garden that cost 1 billion Singapore dollars to build. Its main highlights are 2 cooled conservatory domes that cover 2 hectares in total.
The garden has 3 freshwater display tanks, 2 for Asian arowanas and 1 for arapaima. The photo shows one of the 2 identical arowana tanks. To get a sense of scale, the red-tailed catfish in the picture is about a foot long. The arowanas were hanging out at the top of the tank.