Pseudoliparis belyaevi is a species of snailfish found in hadal zone of the Northwest Pacific Ocean, particularly the Japan Trench.

[4] Pseudoliparis belyaevi is a marine and deep-sea species which inhabits depths exceeding 6,000 meters that was described from a single specimen from 6380–7587 m in the Japan Trench.

[11] Pseudoliparis belyaevi has a slender and elongated body structure, common among snailfish species, and typically displays a pinkish or purplish coloration.

The body lacks scales and instead has smooth, gelatinous skin that aids in withstanding the immense pressure of the deep-sea environment.

[15] In the deep sea, where sunlight cannot penetrate beyond a few hundred meters, there is no need for pigmentation that provide coloration or camouflage as there is no visible light for predators or prey to see.

[17] Liparids have ventral sucking disk that is used to attach to king crab and deposits its eggs inside the carapace of the gills.

However, after the eggs hatch, some species in the family Liparidae rapidly reach the adult size but only live for about one year, while others have life spans up to more than a decade.

Many species inhabit hadal trenches, which are highly turbulent areas with frequent seismic activity and turbidity flows.

[26] Moreover, while it is still being studied, snailfish in the northern hemisphere are suggested to show greater starvation tolerance, possibly due to their varying lipid levels (particularly triglycerol and cholesterol).

However, while snailfish in the deep sea do face predation challenges, they have evolved various adaptations to enhance their survival in this extreme environment.

[28][29] There is limited information available for Pseudoliparis belyaevi and its specific ecological contribution, but there are some potential roles within its ecosystem they may have such as biodiversity support and regulation of the population of small invertebrates.

Pseudoliparis belyaevi and the family Liparidae in general is categorized as "Data Deficient" on the IUCN Red List of Threatened Species, indicating insufficient information to determine their population status.