Common names: worm-fish (English), worm-goby (English), gobio-gusano (Espanol), pez lombriz (Espanol), pez-gusano (Espanol)
Clarkichthys bilineatus (Clark, 1936)
Flagtail worm-fish, Flagtail worm-goby
Body short, stubby, eel-like, with depth ~ 8% of SL; tail (without fin) shorter than head and body; teeth in 2 rows, chisel-like; nostrils tubular; lips not broad and fleshy; gill opening a small tube at pectoral base; dorsal fin origin over pectoral, first 2 spines short, close together, XVII-XIX, 28-32; anal fin II, 28-31; pectoral 11-12 rays; tail 17 segmented rays; pelvic 1, 3; dorsal and anal fins not united with tail fin; scales well separated, sparse on head and belly.
White to yellowish with 2 broad black stripes along head and body: one along midback from snout to top of tail, the other along mid side extending from tip of mouth, covering both jaws, passing under eye to upper operculum and thence middle of tail fin; top and bottom edges of tail black.
Size: 6.5 cm.
Habitat: high-salinity tidepools, and rocky and coral habitat.
Depth: 0-10 m.
The tip of Baja California and Nayarit (Mexico) to Ecuador, and the Galapagos and Cocos.