In case you are still looking for a goby that likes to dig holes, you might think of a Diamond Watchman Goby. I have one and it is fun to watch him keep his area just the way he likes it. He has a cave that is his, and he keeps the entrance covered up with sand so only he can get in. When my small hermits get too close to his cave they get a free ride in his mouth to the other end of the tank. It's great.
55 gallon reef tank. AquaticLife 4-bulb T5 HO with 4 LED moonlights. Reef Octopus BH-1000 HOB protein skimmer. TLF Phosban Reactor 150 running 400ml of NPX Bioplastics with a Maxi-Jet 1100 and a BRS Reactor running activated carbon with a Maxi-Jet 900. Vortech MP10w.