I managed to hook into this nice trevally off a sand island in a small to medium surf. The trevs were cruising the shore and making 'smash and grab' raids into extremely shallow water in the breaking surf in order to nail small dart that were hiding there. I got lucky and managed to drop the fly right in front of them just as they finished a 'raid'.
The trev in the picture is a brassy trevally (Caranx papuensis). This is quite a large specimen for the species. At this size they are often mistaken for GTs. The body is longer in a brassy and the snout slopes more. To be certain look for the white silvery spot at the top edge of the gill plate. Also the end of the maxilla (the top lip) will line up with the front of the pupil in a brassy while in a GT the end of the maxilla will line up with the back of the pupil. Once you get used to the two species the differences in body form make the two species easily seperable.
Brassies are quite common in Aitutaki and Raro, but they are not aways easy. They seem to cruise along in shallow water quite visibly, but do not necessarily eat when they are doing this. They are easiest when they are feeding or are presented with a quiet fly that they can't connect with the angler in any way.
The sand island in the Indian Ocean that this brassy came from had lots of other visible trevally cruising the shoreline, but all of them were very difficult to get to eat. Even getting a response to your fly was often hard. They can be very frustrating when they are like this,so catching a decent one on the nine weight is very satisfying.