strange Oscar fish behavior

Question
I have had my Oscar for 2 1/2 years now.  We rescued him from a bad home and he has always seemed so happy.  When he grew bigger, I got him a larger tank (10 gallon) and again, he seemed to be the happiest fish I had seen.  After getting the new tank, I did some online research and found that I had him in a much smaller tank than he needed, but he seemed content.  The last month his behavior has changed, though.  He seems to be gitting a little bigger, but not much.  He is hardly eating (compared to the hoards before) and he seems a lot more agitated.  He still has his typical behaviors, like coming out from behind the rock when we come in the room, or "sitting" next to me when I watch TV, but he is starting to worry me.  I have had a few ideas, maybe you could tell me if I am on point with some of these and give me more information.  First, I was thinking that maybe "he" is a "she".  I have been noticing some strange, egg-like, clusters when I clean the tank.  Since "he" is so much bigger, I have been cleaning with "him" in the tank.  When I get to this particular corner (the one with the most clusters) "he" gets very agitated and starts trying to fight me.  Otherwise, he calmly stays in "his" rock when I clean the rest of the tank.  Could "she" be laying eggs and being territorial?  Secondly, I was thinking he would like a more varied diet, then maybe he would start eating like he did before.  I have tried "feeder fish", which he liked, but I heard they may be contaminated, so I haven't given them since reading that.  He mostly lives off freeze dried tubular worms, with the occasional piece of liver or hamburger.  He hates those shrimp things!!  Lastly, I was thinking that maybe his tank has something going on.  I keep the water clear and the filter changed.  His tank is a little cooler than recommended, but that is because I live in Florida, and the heater has always kept the water too warm.  It is currently 78 degrees in there.  I haven't done any testing on the water, but maybe I should.  It seems very confusing though.  To end, my fish appears to be healthy.  His scales are the same color and sheen as always.  He has no observable markings on his body that may cause me to believe he is suffering a disease and besides the decreased eating and occasional aggrevation when cleaning the tank, behavior seems fine. Any insight would be appreciated.  Sorry for the long message!!  Thank you.  

Answer
Hi Dawn,
 Are you sure it is an oscar?  An adult oscar is over 12 inches in length and they get that size within a year or so.  You would really need at least a 50 or 70 gallon tank for an adult oscar.

-- Ron
  rcoleman@cichlidresearch.com
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