Cichlids!!! need help deciding if i should keep them all 2gether? any1 who can help me plz!!!?

ok i have cichlids, & here 2 find out i got a couple diff kinds... i have a jack dempsie,oscar,colbalt,ob,electric yellow. so thats 5! ive had the colbalt,ob,electric, for like 5 months. and i bought the jack dempsie like 2 months ago, and the oscar like 3 weeks ago there all in a 55 gal 2gether, do u think that thely b good 2gether? so far no fights or deaths. im just wondering about if they get older then will they begin to demolish each other. im hoping if they grow up 2gether then theyll b fine. any answers? the fish store tells me that the oscar, and jack dempsie r south african cichlids