[7] In response to temperature differences, D. magna has shown both phenotypic plasticity and the ability to genetically evolve to deal with the heat stress of warmer, urban pond waters.

[2] It can be found in fresh and brackish water bodies of different sizes, from lakes to ponds and ephemeral rock pools near the sea.

Nevertheless, compared to other species of Daphnia, it is more often found in association with the substrate where it is able to exploit benthic food sources as periphyton[11] and sediment.

[4] The results of genetic research confirm the deep split between Eastern and Western mitochondrial haplotype super-clades of D. magna.

A narrow contact zone has been found between these two super-clades in the eastern part of Western Siberia, with proven co-occurrence in a single lake in the Novosibirsk region.

Interestingly, Central Siberia has previously been found to be an important contact zone also in other cladoceran species, and may thus be a crucial area for understanding the Eurasian phylogeography of freshwater invertebrates.

D. magna can also feed on periphyton[11] and detritus,[4] an ability that can offer a competitive advantage to this species over strictly pelagic filter feeders in some environments where suspended food sources might be temporally limited.

[13] In response to unfavourable environmental conditions (which could lead to the freezing or the drying up of the pond), the same female can produce haploid resting eggs (usually two at a time), which when fertilised by males, are wrapped within a protective shell called an ephippium.

This behavior reduces exposure of diurnal visual predators (such as many fish) by finding refuge in the dark near the bottom and then feeding undisturbed during the night in the food-rich upper water layers.

Cases of reversed migration patterns are documented when the risk of visual predation during the day is higher at the bottom or in the littoral zones (for example in the presence of fish that hunt within submerged plant‑beds).

[18] Daphnia magna can be looked at as a complex ecosystem, colonized by a community of commensal, symbiotic and pathogenic microorganisms[19][20] called microbiota.

The close proximity of the microbiota to its host allows for a tight interaction, capable of influencing development,[21] disease resistance[22][23] and nutrition.

Some of its advantages for experiments are a fast generation time, limited storage usage, easy and cheap feeding and simple maintenance.

Daphnia magna is used in different field of research, such as ecotoxicology, population genetics, the evolution of sex, phenotypic plasticity, ecophysiology (including global change biology) and host-parasite interactions.

[27] Historically, D. magna allowed researchers to test some interesting theories and conduct pioneering studies: Other recent experiments used the resting eggs of Daphnia present in a pond sediment to reconstruct the evolutionary history of that population in relation to one of its parasites (P. ramosa),[30] an example of resurrection biology.