Mictocaris is endemic to anchialine caves in Bermuda, and grows up to 3.5 mm (0.14 in) long.

[5] Mictocaris is rarely encountered because it lives only in deep waters in the interior sections of the caves.

[6] It is usually seen swimming, but on rare occasions can be found resting or walking on a rock.

[6] It is unknown what Mictocaris eats, but it has developed powerful molar and mandible muscles which allows them to chew productively.

[6] Mictocaris is critically endangered due to population fragmentation, a decline in subpopulations, and only inhabiting a single location.