if your tank is too small, it might create territory issues too until they form a pair
theres a few things you can do...if you have a bigger tank, that may help. you can also wait it out...im breeding a pair of kribs at the moment, and at first they were fighting like crazy...now they get along and are moving into the same cave
convicts are kind of the same way. you can also let them sort their own buisness out, wait it out kind of...but i also got a pair of convicts for some family of mine, and the male ended up killing the female
its all based on the fish's personality. they may very well end up killing eachother
another thing you can do is separate the agressor out of the tank, rearrange everything, wait a couple of days, and reintroduce him. he wont recognize his territory, and it will give the female a chance to set up her own turf