not very clear and s/he is still young, but i would guess it's a male. It has great coloration either way.
I started keeping jags myself. They're so awesome.
Some of the ones you find at the LFS, like Petland, often have muted colors.
pic related:
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That's a wild male from a lake in Nicaragua and a Petland female. He's about 10" she's about 6.5"
She is still beautiful, I will probably get him a wild female as a mate and pass her along to my friend.
(How snobbish of me, I know. She too inbred!) Actually, she's completely fearless . She attacks when I rearrange the tank, each nip removes a little piece of my skin, so the next day there's a red mark there. I try not to let her bite bc it hurts a little...but she can be relentless.
So great character.. and she is totally in love with this male. So we'll see what happens.
Colors can vary quite a bit under different lighting situations as well. Sometimes the edges of the fins look blue-green, other times black.