The one thing that hasn't 't been said about housing the young males separately is build your own divided tank. Plan it out. Have a glass shop cut your pieces of glass and glue it up. Leave 1/16 inch space under the dividers for water flow. The number and size of your compartments is limited only by your ambition. This is really not so daunting a task as you might think and is quite fun. Me? I would make mine 36 inches by 18 inches divided in half lengthwise for two 36 by 9 sections and those 2 sections further divided into 6 compartments of 6 " x 9" for a total of 12 compartments. Let's see now, that's's 1 base 36 by 18 (use quarter inch glass) , 2 sidewalls 18 by however deep you want it and 2 sidewalls 36 by however deep. One divider 35 and 3/4 by however deep and 10 dividers 8 and 3/4 by however deep. Sixteen pieces of glass and a week of your time. Please check my dimensions to be sure. Remember to subtract the thicknesses from the sides to make it fit flush. A worthy project for a worthwhile endeavor.