My 120 gallon has:
1- 12 inch Oscar
1-8 inch GT
1-8 inch JD
1-5 inch Texas
1-3 inch Con
1-3 inch Jag (most likely to be moved when larger, but we'll see)
1-5 inch Raphael Cat
No problems with one 75% wc a week. Keeps my nitrates below 20 ppm. I would say no to your question about being overstocked. Here is my tank.

1- 12 inch Oscar
1-8 inch GT
1-8 inch JD
1-5 inch Texas
1-3 inch Con
1-3 inch Jag (most likely to be moved when larger, but we'll see)
1-5 inch Raphael Cat
No problems with one 75% wc a week. Keeps my nitrates below 20 ppm. I would say no to your question about being overstocked. Here is my tank.

