From what this site says, they are both male. It says the black dot on the back is absent(or nearly so) on the females. Of the ones I have and the others I've seen at the lfs this has been accurate. If you look at my specs, it would be hard to believe that the jewels run the tank. Last night while the larger male and the female were doing a mating dance, the puffer and the jack were getting the snot beaten out of them by the smaller male. He was acctually protecting the lovers from 2 fish that could easily kill him.
