Ventrifossa saikaiensis is a species of rattail.

This is a deep-water fish found at depths of up to 740 m.[citation needed] It is found in the waters off southern Japan and northeastern Taiwan.

[citation needed] It has a pointed snout, a large, inferior mouth with a dark margin on the upper lip and a long chin barbel.

The first dorsal fin is entirely dark, lacking the contrasting patches seen in some members of the genus.

There is a large bioluminescent organ located between the bases of the pelvic fins.