Threadfin Dartfish
The Threadfin Dartfish - Ptereleotris hanae is also known as Blue Hana Goby.
It is pale bluish gray to bluish green upper body and darker blue below; tail of larger adults trail 1-6 filaments.
They takes shelter under rocks or inside burrows shared with Shrimp Gobies.
Very shy and difficult to get close to.
"Ptereleotris hanae", the Blue hana goby, is a species of dartfish native to the western Pacific Ocean. It is a reef inhabitant, being found at depths of from 3 to 50 metres, though usually no shallower than 6 metres. It inhabits burrows made by alpheid shrimp, but unlike the "Amblyeleotris" gobies who normally associate with these shrimp, this species has no interactions with their shrimp hosts. This species can reach a length of 12 centimetres TL. It can also be found in the aquarium trade.