Sorry, Dawn. You can try posting your query on http://www.wetwebfotos.com/talk (though there may be a problem signing up). Or, email the crew. Apparently no one here has the experience (myself included) with Tiger Gobies to help you.
Sorry I missed this post earlier but I do have experiences with this goby. It's not aggressive at all except perhaps to other specimens of the same species. It's scientific name is Valencienna wardii. They are avid sand sifters and I actually don't recommend them anymore for reefs as they'll quickly eat everything in your sandbed (and may starve afterwards).