they will do that.. i've had my 6" red claw male (and for a few months a female the same size.. before he tore her up) in my 55g community. i have mollies, a small pleco, silver dollars, giant danios and have had very few casualties. I once watched him kill and eat a blue ram but other than a few instances where i may have been gone for a few days or my autofeeder ran out he is fine eating algae disks and shrimp pellets
thats because convicts can not be killed.. i have a 1" con in a tank that has NEVER had a convict of any size in it.. the only thing that ever came in contact with a tank that was ever in contact with convicts was a plant that was in contact with the convict tank for about 30 seconds..
i cant catch the bugger.. i want it to be in the worm farm.. but at the same time i fear that either all my worms will be eaten.. or they will birth convicts as soon as they come in contact with water...