Eusthenia nothofagi is a species of stonefly in the family Eustheniidae.

[1][3] This insect lives in streams in temperate rainforest dominated by myrtle beech (Nothofagus cunninghamii) and wet sclerophyll dominated by mountain ash (Eucalyptus regnans).

It is similar to Eusthenia venosa, but its wings are more red than solid purple.

Threats include climate change and clearing of the local forest habitat.

As of 1991 the insect was thought to be extinct, but subsequent surveys recorded its distribution.