I have 5 oscars in a 4' tank. I think 2 might have paired up, they have always been close. Over the last week or so i have been trying to vent them, i think if it works i have 2xfemale 3xmale. The funny thing is that the 2 that seem close look to be both male. and while there is minor fighting between all others they dont seem to fight. So today one of them has decided it dont like my albino tiger female(?) and is ripping off scales and is getting nasty. She now is missing a number of scales and looks quite worried. My big red who rules the tank normaly would break it up but is now just sitting back, and even getting nasty to the others.