oscars sudden aggressiveness

Question
Was wondering why all of a sudden my oscar has gotten vicious. I have a variety of fish in my tank and he has gotten along with them since all the fish were 1-2 inches long. I also used to be able to pet him but now when I put me hand in the tank he has taken good nips at me. I do have a nother oscar in the tank and was wondering if maybe they might some how be breeding becasue the mean one has been digging in the center of the tank for the first time.And all this aggression has come with in the last 2 weeks.

Answer
Hi Mark,
 Basically your oscar is maturing.  It may be that he or she is thinking about breeding.  Unfortunately, it isn't going to change back to the way it was.  This is why oscars almost always end up in a tank either only with oscars or by themselves.  His next move will be to eat his tankmates.  Oscars are wonderfully interesting fish but they do not play well with others.  

-- Ron
  rcoleman@cichlidresearch.com
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