I have two young convicts in a 20 gallon tank. The female is slightly bigger, and she is terrorizing the male.

Question

Will she stop all of the chasing and torturing long enough to get knocked up? Why is she so agressive toward him?

Answer 1

It's part of the nature of convicts to be agressive. First, are you sure you have a male and female? Rather than going by size, look at the coloration. The female will have pink or orange coloration on the abdomen and the tips of the dorsal (top) fin will be more rounded along the back edge. The male lacks the pink/orange and the dorsal will be longer and pointed. If you have 2 males, they will fight until one kills the other. If this is your case, I'd take one back to where you got it and exchange it for a female (now that you know what to look for). Also, if you want them to mate (which they can do from the time they're about 1 1/2 inches), did you provide them with a cave in which to lay the eggs? A clay flowerpot, not much bigger than the pair of fish and turned on it's side will do nicely.

Hope you're sending out birth announcements soon!

Answer 2

Females do not get nearly as large as the males, and do get an orange or reddish coloration on their bellys and lower part of the tail. Males generally get a bulbous growth on their head.

Somewhat juvenile male:
http://www.aqualandpetsplus.com/Cichli1460.jpg

Female convict. Note the orange coloration.
http://www.lilviv.com/pets/fish/ocean180/fem_convict2.jpg

I have found one of the best things to use to allow for the female to lay eggs is to give her a safe place to do so. Even though you know there are no other fish in the tank, the fish has no idea and will need to feel protected. When I used to breed convicts, I found the clay gardening pots did very well. Sometimes covering the glass with newspaper to shield external distractions is good too.

Get the plain pots, not ones with any glaze or decoration. You can break them in half or leave them whole, but they are awesome for creating cave like areas.

Keep in mind, even a breeding pair of fish may not be great parents. After the eggs hatch, the father may eat them and the mother will try to defend. Sometimes the males will kill the females and eat the babies. it is best to separate the parent fish from the hatchlings if you want a high survival rate.