I have a 30 gallon which has previously been home to 5 RBP's and an RTC [at seperate times obviously] all have been eliminated from the face of the earth and after the tank being empty for a few months want to get fish again. I have ordered a 1000 litre per hour external filter and would like some awesome fish. to give you an idea i like snakeheads, rbp's, rtc's, etc. obviously these are all to big but thats just to give you an idea what fish i like. around 9" mark i imagine as the tank is 12" depth. Gars , peacock bass etc are some more fish i like. need suggestions on what fish i should put in, predatory/aggresive/ugly is what i like