If you don't have a sand sifter goby...move it to the bottom of the tank in the sand on its side. It being all spread out like it is in your pictures is not what they look like in the photos I have seen of them. They look like all tentacles..yours is all splayed out and all mouth. You can always move it back if it is unhappy...but try it and see, handle it as little as possible when you move it.
I did some searching, they like bright lights like an anemone...feed it small chunks of raw shrimp, they will eat small fish, shrimp and even snails. They also eat fish poop, phytoplankton, and cyclops. My book says position low in the tank, they prefer sand but can be put on rock...on thier side
Hope this helps.