Feed some earthworms and up the temp a little and with primo water conditions if one lays eggs its a girl. I have one that I was convinced was a boy and then it covered her tank in eggs.
You will have to net each fish in question, flip them over and then refer to what you see in the pics to determine sex. Once this is done you'll know exactly what you have and never will have to do it again. A few moments of handling an upset fish is worth it. Just be careful while holding them. Be firm but not too much. You don't want to hurt them or yourself.Will I be able to see this by looking at him/her or do I have to try to hold an angry, wet 12 inch fish upside down?
I don't really keep cichlids and have never vented before.