Bumblebee Gobies

[xvCODY]

I've had 2 BBGs in my tank with Smudge for quite some time now. They both seem to be doing quite well but they're still <1 inch. I had a random question, though. 1 gobie is bright and vibrant yellow/black and the other is black/pale. Is there a reason they are different colors? Different sex maybe? They don't seem to be bullying each other so i figure it isn't a sign of stress. Like i said, they're both doing great but i figured i'd still ask. ;]

[Tim]

The males are brighter where as the females are pale I believe.