This is the info I came up with. Nothing about color changes...
Sailfin Blenny, Lawnmower Blenny - Salarias fasciatus
Also known as: Jeweled Rockskipper, Jeweled, Rock Blenny
Reef Compatibility: Reef Safe.
Maximum Size: The Salarias fasciatus grows up to 5.5 inches.
Sizes shipped: Sml. 2.0 Inches, Med 2.5 Inches, Lrg. 3.5 Inches.
Minimum Tank Size: The Sailfin Blenny, Lawnmower Blenny prefers a tank of at least 20 gallons with plenty of places to hide & swim.
Diet: The Salarias fasciatus is an omnivore and likes to feed on detritus and algae.
Level of care: The Sailfin Blenny, Lawnmower Blenny is a medium maintenance fish.
Compatibility Notes: Generally peaceful towards other tank mates, but may act aggressively towards other Blennies.
Water Conditions: Keep water quality high (SG 1.020 - 1.025, pH 8.1 - 8.4, Temp. 72 - 78° F).
Range: The Sailfin Blenny, Lawnmower Blenny is commonly collected from the Indo-Pacific, Coral Sea, and Red Sea.
General Notes: The Sailfin Blenny, Lawnmower Blenny is an interesting species for either a fish only tank or a reef type set up, and will add some activity to the tank environment. Will mainly swim within close proximity to the rock of the tank, where it will perch from time to time.