I bought two pairs of Convicts (pink and normal) at a local pet store when I noticed they were pairing off. I put them all into a 110 liter tank, hoping they would stake their claims and breed. The black pair bred first, and kept the pinks in a tiny corner of the tank, so I bought a tank divider and gave the pinks about a third of the tank while I set up another for them. When the time came, I removed the pink pair and pulled the divider. The black pair and fry moved in, and things were smooth. Until the next day, I noticed a cloud of fry left by the pink pair that they had hid from me. I was worried, but the blacks attacked me when I attempted to get the fry, so I left them. Two weeks later, the blacks are taking care of two broods of small fish that are doing fine, while the pinks are digging pits for a second try.
The Convicts are for sure an interesting species! Agressive - yes! I have just recently added these to my community 250 litre community aquarium. I have 3 females and one male. The only one who shows their true nature is the large male (13 cm) and his "alpha"-female. The other two females are "benevolent" towards the other fish (Clown Loaches, Neon Tetras, Green Nigers, Corys, Gouramies (blue), Orangefin Loaches and Angelfish. The male and the female soon began to "reorganize" my aquarium, and made themselves a territory around a cracked flowerpot I placed in the gravel. They are especially aggressive towards the other two Convict females. I watch them closely everyday to see how they react to the other fish, they have not yet begun to produce fry, and from the other comments on this page I might see another scenario then, but up until now it all works fine since the aquarium is relatively large. The only fish that has actually turned around and attacked the chasing male is my largest Angelfish (after all he is also a Cichlid). Furthermore, it seems to me that my male Blue Gourami is keeping them out of his nesting territory. My Convict pair does not go off the way to nipple aggressively at my hand when I am trying to "patch up" some of their most ravishing reorganization of my aquarium (they move gravel around big time!). I believe for sure these Convicts are worth their money - you will enjoy them as long as you take certain precautions (size of the tank and tankmates).
I have a 200 L tank in my living room with 14 Convicts, 1 Jack Dempsey, 4 Rainbow Cichlids, 1 Giant Danio, and 2 Cory Cats. The Convicts are the most interesting fish that I keep. I also have 8 other tanks with various types of Cichlids. The biggest male in the 200 L keeps all of the other fish completely on the other half of the tank (this includes the Dempsey). His spouse has laid 2 batches of eggs in the last three weeks. The only thing that has saved me from being completely overrun with baby Convicts is that the zygotes usually get eaten before they become free swimmers. They are the most aggressive fish that I keep and by far the most fun to watch. If you want a "fun fish" raise Convicts!
I have a Convict who is very mean and aggressive he is 25 cm and beautiful. Convicts are the street brawlers and have a horrible attitude, but they´re cool fish to have. Convicts don't play so make sure you keep them with very aggressive Cichlids like Mbuna, Buttikoferi, Jack Dempsey and the beautiful Green and Red Terror.
I have found that the Convict is grossly overrated in aggressiveness. Its aggression is no more than many other Central American Cichlids and only famous because it is a common fish. If kept with other fish such as managuense, devils, festae, umbies, etc, the convicts will either get eaten or mutilated. I have an 18 cm Jaguar which is way more aggressive than my 8 cm male convict.
I had just bought two Convicts about a month ago, later finding that the shop had accidentally given me two females. I then bought an additional male from the owner and placed it with one of the females, instantly pairing off! Three days later the female had spawned in a cleaned out flower pot! I am now waiting for the new fry as I begin the journey of breeding cichlids.