[8] Neolithodes diomedeae are opportunistic, necrophagous scavengers.

[4][9] In the Gulf of California's abyssal plain, they live around hydrothermal vents and feed on organic material which falls from the pelagic zone.

[4] In deep-sea sedimentary habitats, young N. diomedeae have been found to have a symbiotic relationship with sea cucumbers, frequently situating themselves on or underneath members of the genus Scotoplanes.

This relationship is hypothesized to be related to elevated food availability and shelter from predation.

[10] They have also shown an affinity for situating themselves on corals, especially as juveniles.