If you want to see your goby more during the daytime, you might want to give him a reason to come out: food. Around 7 inches he should start getting spots near the end of his tail. The pattern will move forward, consuming the iridescent bands of gold. Around 10 or 11 inches, no more gold bands. At least, that's what has happened in my experience.
Some good tankmates might be bumblebee gobies (I love those), OR knight gobies (they might eat BBGs). Livebearers like guppies or mollies work, but they reproduce quickly and can add a lot to the bioload eventually. Assuming you had a very large tank, you could probably have some land in it and keep mudskippers. If you go for the mudskippers, I would pick Indian mudskippers. They stay small and aren't as aggressive. I've read that ropefish are brackish, but they get pretty big and are bottom dwellers, so the goby might get territorial.
I hope that helps.