Black Convict Breeding

[MC1973]

I heard once they breed, they kill everything else living (threat) in the fish tank. I have 1 black convict and also 1 jack dempsey in the tank right now...I want to add more fish and also I like the black convict, but should I avoid adding more black convicts in case they breed and decide to mass murder everything in the tank?

Is this how all cichlids are?

 

[Kneedeep kowboy]

I had green terrors breed, very exciting! The mom and dad watched over the babies and would gather them up at night by suckin em up and spitting em into the nest, I know that's not black convicts but they never went out and killed everything, maybe the occasional "back up" peck on my Oscar, but that was it, ofcourse the Oscar is bigger which may have had something to do with it, but from what I've seen cichlids are unique and act accordingly.