Prosecutors are investigating who is to blame after more than 10,000 fish have died while waiting to be moved to a brand-new Brazilian aquarium development.

Billed as the largest freshwater aquarium in Brazil, the R$166m (US$53m, €48m, £34m) Aquario do Pantanal in the western city of Campo Grande was originally scheduled for completion at the end of 2014. Construction work however was significantly delayed and the aquarium is yet to be finished.

Imported from Africa, Asia and Oceania, the fish had been in quarantine with a company called Anambi since November. According to the Folha de Sao Paulo newspaper, 80 per cent of the population of more than 12,000 fish died from a temperature drop as winter approached in the southern hemisphere country.

However, government officials say technical failures in the temporary tanks are to blame, including poor oxygenation, the presence of bacteria and inadequate cleaning. If everything had gone according to plan, the fish would have been transferred to their new home more than six months ago.

Designed by architect Ruy Ohtake, the 17,000sq m (182,000sq m) development has not had a date for completion finalised. Once open, it is hoped that the aquarium will attract thousands of tourists to Campo Grande, which acts as the main hub for people travelling to visit the Pantanal – the world's largest freshwater wetland.