On sexing your cichlids, it depends on which ones you have.
Americans are sexed by their fins, Pointed "On most", is a male or rounded "on most" are females.. actions as in spawning, males are aggressive and they are the nest builders to attract the female, Females hide as they are not ready to spawn and the males always are and so forth. A lot like the Africans in spawning behavor..
Oscars can only be sexed by venting OR 4 in a Lg tank, 125gal+ and wait for them to pair up. Take the rest out or they wil kill/injure the others.
Most of the south Americans, mostly the cichlasoma speices develope a nuchal hump to distingush the males from the females at an early age. Males develope this HUMP on their forheads to attract the females. Females get these later if any at all. Red Devils and Midas are the main species to get this humps, they are fat cells that absorb water to increase in size at spawning time and go down after wards..LIke my avatar, Male Midas...
Africans, are mostly determained by their Egg spots on the bottom lower anal fin under the tail. MORE distinct spots, chasing, digging "nests" and VERY aggressive to others, is a male, NONE or less distinct spots and less aggression, Hiding alot, as in playing dead at the top by the intake tube/heater,, is a female.
Others like the E.Yellows are sexed by colors, more black on the bottom fins "ON MOST", is a male, less to none, females. Body size playes a big roll too. males are bigger than the females.
Keniys are a speices that are the same colors, blue body black stripes at juvenil stage, the males turn golden when they are maturing at 4 mos old. The females stay the blue/stripes. but some females wil turn to a light golden color to throw off the male, but is a dull color and can stil be distingushed as a female.(yes I have these cichlids with an older female who is this color..)
On hap speices, most females are a grey/brownish color to distinguish the sexes, the males are brightly colored..
A lot of Africans, depends on the species on sexing them, most are easy to impossible if you don't know what to look for.
I Hope this helps you figure out the sexes a lot better.
Barb