The temperature of the surface waters of Hartz Lake varied between 2.6 and 25º C during the 12-month period of the study. The waters of the Hartz lakes are oligotrophic but due to their enrichment with Na⁺ they are not typical of water from other areas of dolerite in their cationic proportions.

The rock fauna of the lake and creek were sampled four times in 1974. The rock fauna is dominated by crustaceans if the actively swimming Anaspides tasmaniae is included.

The fauna of the creek is richer in number of animals and species than that of the lake. It is dominated by insects.

The dominance by crustaceans of the rock fauna of this lake contrasts with the insect-dominated rock faunas reported in other Tasmanian and European lakes, and may represent the situation in Tasmanian highland lakes where trout have not been introduced.