Join Date: Oct 2008
Location: Fringe of Windsor Great Park, England.
That picture looks to me like a male, Gobies.
It's not easy to tell the sex until they are nearly adult, and you really need one of each for comparison.
The largest male I ever saw [the father of all my shrimps, from the I guy mine originally came from] was over 4 inches long, with enormous arm and claws. The Alpha male in the tank grows much bigger than the other males, maybe because he gets the most food, or perhaps the secondary males somehow restrict their growth so as not to be a challenge to him. I know that when this BIG DADDY died, one of the other males began to outgrow all his brothers [new alpha male, I guess].