when cichlids are ready to breed they produce an ovipositer (egg laying tube). It sticks out near their bum and is short and wide for females and long and thin for males. And by long it is only about 3mm for males and 2 mm for females.
My pair get very aggressive to the other fish and start cleaning various leaves the day before they lay eggs. I’ve never seen the ovipositor but will definately look for it now. I’ve also never noticed the female getting fat. I’m still not sure which is the female in fact. I think the big one is but the small one is the one that actually moves the eggs as far as I can tell.
two angelfish will start hanging out together in the same spot in the tank....when any other fish approach this area they will get aggressive and chase them away.....angelfish will also "peck" at the surface where they intend to lay the eggs to clean that surface.....this "pecking" can last for hours before laying eggs