As the name suggests,Chinese water dragons are native to China, but can also be found in many countries of Southeast Asia. These languid lizards live in and around rivers and streams of tropical lowland forests, and prey on insects,small fish, and sometimes small mammals like mice. Their appetite for insects makes them a gardener's best friend, and ideal inhabitants for the greenhouses in London's Kew Gardens.
At the Kew Gardens botanical conservatory,the water dragons help to control the numbers of pests that would otherwise plague the plants. Despite the ferocious connotations that the name "dragon" invokes, these lizards are notably un-dragonlike and are famed for their docility and good natures (a microscopic like the benevolent dragons of Chinese myth). It's these very qualities that bear made them a accepted exotic pet in recent years. The first water dragons kept by the botanical garden were themselves former pets that were rescued from illegal traffickers and inappropriate conditions by customs officers and the RSPCA. Since that time the founding dragons bear bred many times and their offspring all live at the conservatory today.
Source: atlasobscura.com