An eel specimen found on the bank of the Whangaehu River, Mt Ruapehu, in late October/November was examined to determine its species and age, together with its gender and sexual maturity, and also to assess its probable movement pattern prior to death. The location at which the eel was found is significant because it is about 6 km upstream of the Tokiahuru/Mangaehuehu confluence, which used to be a traditional eel fishery location for the local iwi Ngati Rangi, and is the first part of the Whangaehu River where its acid volcano-fed waters are significantly diluted. The specimen was shown to be a subadult female shortfinned eel (Anguilla australis), 795 mm long and 1526 g in weight. Age was estimated from sagittal otoliths to be about 31 years in freshwater, and it had lived in a limiting habitat in the last 13 years. Although "average" water quality has probably improved in the Whangaehu River above the Tokiahuru confluence since the 1995/96 Ruapehu eruption, any causal relationship between that and the eel's location may be coincidental.