Red devil cichlid, female or male

[Perhaps]

I have 2 red devil , and this 2 never fight , I have the smaller one first 20cm and recently I got the bigger one 23cm. The big one will try to kill all others fish no matter big or small if I added them to same tank but he don't fight with this red devil

Been told that small one is female and bigger one is male, see pic, with their vent picptoo.

Try to breed them but nothing happened , never see the female lay eggs too.

Also they seem always try to attack the other fish from the bottom mirror?how to stop them? Did try to cover with gravel before but they will still move the gravel

 

[tlindsey]

I have 2 red devil , and this 2 never fight , I have the smaller one first 20cm and recently I got the bigger one 23cm. The big one will try to kill all others fish no matter big or small if I added them to same tank but he don't fight with this red devil

Been told that small one is female and bigger one is male, see pic, with their vent picptoo.

Try to breed them but nothing happened , never see the female lay eggs too.

Also they seem always try to attack the other fish from the bottom mirror?how to stop them? Did try to cover with gravel before but they will still move the gravel

View attachment 1344229 View attachment 1344230 View attachment 1344231 View attachment 1344232

The 3rd pic looks male left and female right. I'm going by the pointed dorsal and nuchial hump.

 

[Jexnell]

This is my first go at breeding Amps. Mine are Saggitae tho not RD's, but still very simular.
What I noticed is first they dug a pit for the fry after hatching. Then laid eggs.
It looks to me maybe they your pair are trying to dig the pit and can't. Then also they are "seeing an invader in thier pit area" so trying to get it out of thier area.
I would suggest if you can get to the bottom glass to cover it with black paper or some thing to stop the mirror effect. Then maybe deepen the substrate some so they can get the "we dug a pit" part done.

My pair is a 4in male and maybe 3in female. But over the last four days or so have dug out this huge put.

See how they have dug down to the bottom glass thru two inches of gravel.