[2] The species' common name, "flagfin stargazer" refers to the structure's resemblance to a small flag atop the blenny's spine.

[2] Its body is elongate and compressed, primarily creamy-white, with eight reddish-brown saddles and blue chromatophores on the head.

The esca-like structure is at the tip of the elongated spine on the first dorsal fin and is reddish brown.

[2] Williams describes G. inescatus as being similar to G. uranidea, G. healae, and G. jacksoni, with the esca being a noticeable distinguishing trait.

[2] The full extent of the distribution of Gillellus inescatus is uncertain, as it is only known from the holotype specimen, found between Northwest Point and Lulu Bay, Navassa Island.