Please help!! I have a 30gal tank that I have had for over a year. Ph 7.1, Nitrites 0, Nitrates 40, Temp 78. I have 2-Angels 4 1/2", 2-Figure 8 Puffer 2", 1-Pleco, 1-Cory. Over the last month my female angel has been bitting the male. She has ripped off his lips and part of his forehead...