I'd go with female based off the more rotund body and rounded head, but it's not a very good picture and it's a small specimen. So, really just a guess.
male, better pics will tell us for definate, you can find out if you look at the anal and dorsal fins, they are generally longer and pointy at the ends.
I think its probably a male, because of the pointy fins and color.
A male GT should have (when it is adult, anyway) long trailers on its dorsal and anal fin. They usually go back about as far as the tail. Also, much more color, and sometimes they can develop a nuchal hump.