Of the easy to find fish I'll say midas or dempsey. Out of the less common I'll say V. argentea,Amph. rhytisma,chauco intermedium,chauco godmanni are great also. Out of the little less common there are paraneetroplus gibbaceps, theraps lentigennosium,theraps irregulare, tomocichla seiboldi(really vicious). Out of the darn near impossible I'll say Amph. bussingi, paraneetoplus bullerri