The fauna and flora are unique in Lake Hévíz due to the temperature and chemical composition of the water, which contains carbonic acid, calcium, magnesium, hydrogen carbonate, reduced sulfuric compounds as well as oxygen in solution.

Most common Cyanobacteria are filamentous blue-green algae (Oscillatoria princeps, O. tenuis, O. jasoruensis, O. chlorina, Spirulina major).

These together with the bacterium species play an important role in the lake's sulfur cycle.

Micromonospora heviziensis for instance, a very powerful protein and cellulose decomposer, can only be found here in the world.

Microbispora amethystogenes on the other hand, which accumulates iodine in its cells, is to be found in only few lakes in the world.

The biodiversity of the phytoplankton is poor and its biomass is low, thus the lake's trophic level ranges from oligotrophic to mesotrophic.

Also a unique Hydracarina acarus is said to have found its habitat outside the fence surrounding the lake.