This is the shy Graceful Partner Goby Lotilla graciliosa with its commensal Red Spot Snapping Shrimp Alpheus rubromaculatus. Unlike most gobies that lie on the sandy bottom, the Graceful Partner Goby seems to hover just above it, constantly flapping it's spotted fins. This is the first pair I've noticed in Timor and had to wait 20 minutes for them to come out for a photo shoot.