BWG and YWG, whats the difference?

[romsoccer12]

Is there any different between a yellow watchman and blue watchman? i wanna add a BWG to my 29gal tank because i also wanna add a yellow clown goby and i dont want 2 yellow fish.

 

[chrisstie]

The blues seem to get a bit larger than the yellows from what I have seen.