I dont see any sign of a nachul hump at all, so I'd say female, but its hard to tell at that size. Some males dont develop much of a hump, or develop one later
At that size they are very hard to tell if its female or male without venting it. not the best way to judge a gt. But by going by the dull color, lack of a thick orange on the fins and body shape i would say female. Again not the best way judge though....example alot of people said mine was a female at that size but come to find out , its a male When he is around 6-7 inches it will be easier to tell the sex. Good luck