[7] The slime is notoriously difficult to remove from fishing gear and equipment, and has led to Pacific fishermen bestowing the nickname of 'slime eel' on the species.

[8] Slime production in hagfish is also an energetically costly process, and regeneration has been shown to take a long time.

[10] The Pacific hagfish also has a transparent window of skin stretched over the eye, which appear as white spots on the fish.

The increased eye complexity found in Eptatretus stoutii may relate to their ecology, as some species within this genus have been observed exhibiting predatory hunting behavior.

[11] The Pacific hagfish confused scientists at first because Carl Linnaeus mistakenly classified the organism as an "intestinal worm".

[4] It inhabits fine silt and clay bottoms on the continental shelves and upper slopes at depths from 16–966 metres (52–3,169 ft).

[1] The Pacific hagfish also was discovered off the coast of Costa Rica in 2015, which extends the southern part of their range by roughly 3500 kilometers than was previously thought.

[14] While Pacific hagfish likely take polychaete worms and other invertebrates from the sea floor, they are also known to enter dead, dying or inhibited large fish through the mouth or the anus, and feed on their viscera.

[15] Additionally, hagfish do not actively drink water, as their internal salt concentration must match the surrounding seawater.

[16] The feeding apparatus of hagfish is unique among fishes and is primarily composed of soft tissues and a prominent dental plate.

This use of this plate in practice resembles a grasping and tearing motion and relies on muscles that run posteriorly from the head.

The outer layer of a hagfish’s skin acts as an ideal surface for creating knots with low friction.

[22] This is accomplished by a combination of factors, which include blood volume, a large subcutaneous sinus, and loose skin.

[22] Since this sinus is loose and constantly filled with fluid, the hagfish can push the blood to other parts of its body, which is what allows it to fit through such small openings.

The skin itself is not puncture resistant, but allows internal organs and musculature to move out of the way from penetrating objects (Boggett 2017).

This contrasts with fishes such as teleosts, which have tight skin attached to their body core allowing for more sustained damage from puncture wounds.

[23] The Pacific hagfish employs an anguilliform swimming mode, as it has an elongate, eel-like body plan.

A study found that both E. stoutii, and Myxine glutinosa (Atlantic hagfish) utilize high amplitude, undulatory waves to swim.