Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Subclass: Pterygota
Infraclass: Neoptera
Superorder: Exopterygota
Order: Plecoptera (stoneflies)
Family: Gripopterygidae
Genus: Zealandobius

Stoneflies of the 'Zealandobius' genus is a group of small stoneflies. There are about 29 named species in this genus.
Zealandobius nymphs pray on plant material, Calothrix (bacteria), Cocconeis placentula and Rhoicosphenia curvata (diatoms), detritus (dead particulate organic material), Staurostratum and green algae.

These invertebrates play an important roll in the freshwater ecosystem. They do not just provide food for the trout but their presence indicates the water quality such as clean water, low-temperature 8-10 C and high oxygen levels. Scientists count the invertebrate numbers present in the streams and rivers, thus monitoring the water quality.

Stonefly Plecoptera of the Zealandobius genus 2.jpg  

Stonefly Plecoptera of the Zealandobius genus-001.jpg

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/