Yellowstripe Fusilier

Found in schools, feeding mid-water in the water column, often with other caesionids. Varies in colour, from blue to red with night and day.
Eastern Indian Ocean - Indonesia, Maldives

Fusiliers are close relatives of snappers, but are much smaller and more slender.
Schools of fusiliers often have other species mixed in.
Although their colour is predominately yellow/blue, at night and when resting their colours change to red/green.