Still think it is a frillfin. Below is from fishbase. Look at its pectoral fins. States 4-5 outer/upper rays free. I think I see this in one of the photos. Maximum size six inches in the wild.
Dorsal spines (total): 7;
Dorsal soft rays (total): 8-9;
Anal spines: 1;
Anal soft rays: 7 - 9. Diagnosis: body with 3 broad, oblique, dark cross bars; numerous pale striae along sides, corresponding to the center of each longitudinal scale row; head and pectoral-fin bases with white spots and mottling; predorsal scales extend well anterior to level of preoperculum, and anterior margin of scaled area appears convex in dorsal view (Ref.
57403,
79590). 4-5 outer/upper pectoral-fin rays free (Ref.
57403,
79590), hence its name "Frillfin goby" (Ref.
26938). Body shape is terete, slightly depressed; eyes situated dorso-laterally; reduced swim bladders (Ref.
92840).
