Scientific name: 
Thalassoma lucasanum
Distinctive features: 
TP: 1. Wide yellow saddle patch behind head and above pectoral fin. 2. Blue to purple head. IP: 1. Bright yellow midbody stripe.
TP: 4-5 in. max. 6 in. IP: 2 1/2-4 in.
TP: Body varies from violet to reddish green; blue dorsal, anal and tail fins. IP: Dark back, may display a second yellow stripe below dorsal fin. Belly white.