Hey i highly recommend cichlids as well. i have a 170g south american cichlid set up that has 2 jack dempseys, 2 convicts, 1 oscar, 2 jaguars, and a rather large and plump pleco. all these fish are tough and are full of life (less the pleco). just make sure you stay up on your water changes and your filter media. if you forget to swap out or recharge your carbon the system will fail!!

best of luck