Scientific name: 
Abudefduf saxatilis
Distinctive features: 
1. Five black body bars. 2. Upper lip does not overhang lower.
Size: 
4 - 6 in. max. 7 in.
Upper body usually yellow, occasionally with shades of green to blue, and white to bluish silver or light gray below. Male becomes dark blue to purple during mating season when guarding reddish purple egg patches.