New Zealand Longfin Eel Anguilla dieffenbachii

The New Zealand Longfin Eel spends most of its juvenile and adult life in freshwater streams, rivers and lakes of New Zealand. It is endemic to NZ, unlike the Shortfin Eel. A long-lived eel (up to 100 years if it evades fishermen), they spawn only once at the end of their life, thousands of miles away in the ocean off Tonga. The eel's early life is spent drifting in ocean currents back towards NZ, then as a glass eel in estuaries, then as an elver in streams before becoming an adult well upstream. Elvers can climb almost vertical surfaces of several metres height.

The New Zealand Longfin grows to over a metre for the larger females. The dorsal fin starts nearer the head than that of the Shortfin, taking about two thirds of the body length - longer than the anal fin (both dorsal and anal are a similar length in the shortfin). The survival of the Longfin is under threat, especially with continued fishing and its once-off lifetime spawning.