I have a soon-to-be-empty 65 gallon tank. I am trying to get some ideas of what to keep next. I am not interested in any "comon sense" suggestions such as angels/discus, african cichlids, etc. that come to mind based on this tank's dimensions (36x18x24). I want something aggressive that prefers soft water (Ph 6.5-7) and can live in this tank for life. Not opposed to SA cichlids and may even consider going brackish or bufferi g water for higher Ph but would like to explore other options first. Also, the tank has a sand substate and is located in a spot where it gets a fair share of direct sunlight, so whatever species I will be keeping should not be light shy.