var vtn_player_type = "vp";var ven_video_key="NTk1NTc3fHwxNDcxfHwwfHx8fHx8";var ven_width="660";var ven_height="409";For the past three weeks huge numbers of fish have been dying in Rio de Janeiro's famed Guanabara Bay, for reasons as yet unknown. Duration: 01:01