The aquarium was separated into three halls, each home to different types of fish and other aquatic wildlife. The first hall primarily contained freshwater species such as rudd and European eels, as well as some saltwater species involved in various conservation projects and captive-breeding programmes, such as broad sea fans, uarus and seahorses. The second hall displayed various species of coral reef fish from around the world, such as clownfish, copperband butterflyfish and regal tangs, as well as real coral. The third hall housed species native to the Amazon River, including red-bellied piranhas, angelfish, arapaimas and ocellate river stingrays. As well as the three halls, the aquarium also featured the "Big Fish Tank", which contained large fish species that were all former pets, and had to be rescued because their owners did not have the proper equipment or understanding to look after them. The species in the Big Fish Tank include tambaqui, catfish and pirapitinga.