Halgerda fibra is a species of sea slug, a dorid nudibranch, shell-less marine gastropod mollusks in the family Discodorididae.
This species was described from 3 specimens collected in the Philippines at depths of 92–95 m (302–312 ft). Additional specimens included in the original description are from New Caledonia at depths of 234–402 m (768–1,319 ft).