Here's some additional info on keeping multiple oscars:
Here's my take on the whole two oscars and tank size issues.... It's been my experience that no matter the size of the tank, even an 800, males will simply not get along. The problem comes when you have a tank smaller than 800 gallons one male WILL kill the other. Especially if a female is present. I currently have six oscars in an 800, three are mature, three are not and have not revealed their sex yet. Of the three that are mature only one is female. The two males still hate each other but there's room to run in a 14' tank, not a 240, or a 75. To get two males to get along is not an easy task but it's been done.
In short here's the deal:
F + F = OK
F + M = OK (sometimes)
M + M = No way
That's usually why only one oscar is recomended, not because there's not room for two oscars but because there's aggression issues.
TFG
