I had a Yellow Watchman Gobie pair with my Tiger Pistol Shrimp. The Yellow finally died after a while and I think his buddy ate him @_@
Dont really like the combo tho.... they are very skiddish and dart into the sand under the LR to ANY movements : /
And the Pistol is like a bulldozer, he will bulldoze your sand all day lol.
OH, the reason I think the Goby died was because I put more fish in there (clowns) and since he is so frickin skiddish every time I feed he never got any food cuz he just darted under the rock to hide, and the clowns got it all....
It was fine when it was just the Goby in there by himself for a few months he had lots of time to come out and catch the pieces that floated by his cave XD
idk, maybe you will have a more aggressive goby.... maybe not.