think it might be a male?

[jasonsalow]

so i bought two 1 inch "red devils" at a lfs (probably a mix but its ok with me)..one grew faster then the other and finally killed the smaller one but im new to red devils and i just wanted to see if you guys think it might be a male
first two pics when it was like 2 inches and started to change color
last pic is the most recent at about 4.5 inches

 

[jasonsalow]

oops got the pics backwards but you get the idea

 

[Citrinellus]

Its tough w/ red devils. I've seen some females with huge nuchal humps to find them laying eggs. Your best bet is to let him grow out another few inches probably 7-8". Then show us a picture of his vent.