Pairing Yellow Prawn Gobies (Cryptocentrus cinctus)

Hey guys
 
I am trying to pair yellow prawn gobies and from what I have read is that if you simply put two fish together, they will eventually pair and form a breeding pair if certain conditions exist of course (water temp, water quality, nutrition, etc). I have two gobies in the same tank (30 gallon nano). I am assuming that they are both male because they fight and one is more aggressive than the other. Aggression has dwindled of the past couple of weeks and is becoming less and less violent. I know that the female turns white or pale once paired. 
 
Does anyone have experience pairing these fish and is it probable that a spawning pair will result in time?
 
Here is a video of my gobies squaring off. They no longer do this now. 
 
https://youtu.be/mAMSfnUuQbc

I think the jury is still out about the color change.  My friend's spawning pair are both bright yellow. I raised 2 from one of the nests and the larger one started out gray, and changed to yellow.  The smaller one has always been bright yellow. They live in the same tank, but don't seem to like one another.  i do hope they spawn someday.

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I have been working on pairing these for over a year now. Started with two 1" fish and experienced exactly what you described with initial extreme aggressive behavior followed by less aggressive behavior. One fish did assume a grayish color after a few months. They would constantly display to each other from opposite ends of the tank. The yellow one would rise in the water and puff up its gills, gape its mouth, and shake. The grayish one would respond by laying as flat on the bottom as possible and fluttering its pectoral fins. I did notice the grayish fish eventually changed its display to the same one the yellow fish constantly displayed. That is when it got ugly! After almost a year together they began to fight to the point where I had to separate them. The grayish fish turned yellow within days after separation. As this was the submissive fish, always losing the fights and trying to run, I assume gray could be a submissive coloration display... Then again, you would think that would factor into sex determination as it does with clownfish. Where the eventual male is always the less dominant juvenile. Who knows? Now both are around 3" long, going on two years old, and about as big around as a dime. I plan on getting a small juvenile to try to pair with what I assume are the terminal phase adults.
Sorry for the long post. Hope this helps! And good luck