I agree that it's a male, and also with the Stanzzzz7 on the nuchal hump.
I've never kept a male that got to much of a nuchal hump. I've always kept one male per tank due to aggression. To my excitement to find one at my LFS showing one at only 4", it soon disappeared after I got him home. He was in a tank full of male and female rivulatus which explains the nuchal hump being a male dominance thing for me, but that's just my experience. It may also have a lot to do with genetics, and I just haven't got very lucky.
I have had females develop nuchal humps during spawning though interesting enough.
I've never kept a male that got to much of a nuchal hump. I've always kept one male per tank due to aggression. To my excitement to find one at my LFS showing one at only 4", it soon disappeared after I got him home. He was in a tank full of male and female rivulatus which explains the nuchal hump being a male dominance thing for me, but that's just my experience. It may also have a lot to do with genetics, and I just haven't got very lucky.
I have had females develop nuchal humps during spawning though interesting enough.





