Rainford gobies are one of my favorite fish in the industry.
A very passive fish, it is very colorful and a pleasure to have. As with most gobies, in can be skittish, as sudden movements around the tank will cause it to bolt into it's hole. Might want to make sure that you have a secure lid, so you don't have a jumper.
In regards to the sand shifting style of this fish. While it does not take as much as a orange diamond into its mouth to sift, it will sift a fair amount, much like the Hector goby. It will also pick at the rocks, which helps move any detirus that has collected onto your rocks. Of course, it will also add sand to your rocks, so it is a catch 22 there. Not a lot of sand, mind you, but it will drop some sand on the rocks as it filters.
I am housing one in my little 10 gal nano at work, at it is definitely a fun fish to have. I had been having problems with brown algae in my tank, and this rainford has PLOWED right through it.
While I haven't found a good prepared food that it takes to, it definitely has cleaned up the algae in the tank.
I wouldn't run with a YWG and a rainford, as they are around the same size and body type, along with both living in the same 'zone'. You might be able to get away with it, but only if you were able to get each fish to designate their own territories. I wouldn't count on it.
The wrasse would be too aggressive for the rainford, and would probably nip at it.
