Changuu is the name after the swahili name of the fish which is common in the waters around it throught it is shown as Kibandiko Island on some old maps. But this name is no longer used.
The island was inhabited untill 1860, when the first Sultan of Zanzibar Majid bin Said gave it to two zanzibar arabs who used it as a prison for rebellious slaves prior to shipping them abroad or sell them at the slave market in Stone Town.
Zanzibar became a british protectorate foll owing 1890 heligoland Zanzibar treat with government, this resulted in the appointment of british first minister Lord William Mattew in October 1891 when Lord Mattew purchased changu from it is arabs owner on behalf the Zanzibar government.
In 1893 with the intention of building a prison upon it, the prison was to have housed violent and recidivist criminals from the part of Africa mainland which was under the jurisdiction of Zanzibar.
Despite of prison buildings being completed in 1894 and the island became known commonly as the Prison Island the authorities who concerned by risk of disease ephidemics affecting Stone Town, then East Africans main port.