I've seen a lot of people asking "What sex is my krib?" lately, so I figured I'd put together a helpful guide for everyone.
Caudal = Tail (just a heads up).
So, let's start with the basics. Our fish are called Kribensis or Purple Cichlids, with the Latin name Pelvicachromis Pulcher.
They can grow up to 4" for males and 3-3.5" for females.
Now, for sexing: Males are pretty easy to spot - they're longer and slimmer, with those fancy elongated fins. As they mature, they get a diamond-shaped tail. The Dorsal fin starts off silvery-white, then turns yellowy-gold halfway down. Males usually have fewer "eye spots" on their Dorsal fin, but they've got a big one on their Caudal fin, along with that reddish-gold lining on top. Some good quality males will even have a blue-ish purple colouring on their anal fin and near their Caudal fin. Oh, and some might have a slightly pink belly, but it's never as round as the females.
Females, on the other hand, are rounder in the belly area and usually have that bright red-purple belly once they're mature. They've also got bright yellow cheeks and maybe some blue-ish purple colouring on their anal fin. Their Dorsal and Caudal fins are yellowy-gold, and the tail is always round and smooth-edged. Some good quality females will have a gold "dusting" above their black stripe, but don't count on it. Females usually have 2-3 "eye spots" on their Dorsal fin, which males typically don't have.
I've included some pictures of my own Pelvicachromis Pulcher - my breeding pair.
Hope this helps you figure out what sex your kribs are.