[9][10] E. octoculata prefers acidic bodies of water with low nutrient content.

Levels of contamination can also be determined by the amount of pollutants in the tissues of E. octoculata, which was shown in a study by Macova et.

[13] Due to the lack of jaws or a proboscis, this species uses a pharynx to swallow its prey whole.

[14] In a laboratory study, it was found that E. octoculata will suck in pieces of dead or wounded animals including vertebrates such as fish.

[13] In addition, when wounded chironomid larva is present, this species will uses its oral sucker to retrieve blood.

[8] Vermiform crawling involves an alternating shortening and extending of the body along the tail and oral suckers.

[8] E. octoculata lacks developed sensillae and instead has sensory buds on its dorsal surface due to its predaceous nature and fast moving aqueous environment.

[8] Spread through the center of each annulus, these sensory buds have a round, raised appearance on the dorsum of this species.

[18] Freshwater leeches need to constantly remove excess water along with waste products.

[19] Adult leeches are distinguished by the presence of a clitellum, where its oval shaped cocoons are secreted from.

[19] Variations between lengths of the life cycle can potentially be explained by environmental conditions such as water temperature, food availability and dissolved oxygen.