what sex is my JD and why is it so aggressive?

[Bluegilllover12]

i need help you guys i have no idea what sex my jack Dempsey is its 3.5 inches long and some days it has the coloration of a male and other days it will have the coloration of a female btw its tank mates are a 4.5 maybe 5 inch bluegill and an almost 4.5 inch Golden gourami the gourami is a female the bluegill a male View attachment 1128957

 

[SmokeyDaScarecrow]

It is a female Jack Dempsey and a beautiful one at that. the way you can tell is the spots on its neck. it doesn't have spots on its stomach. It is not too aggressive because my female ate my kuhli loaches, beat up my Red Jewel who is bigger than her and bit off a BGK 2 white strips on it's tail.