Oscar fish not happy

Question
i've had my oscar fish for 6 months he has been growing and egarly feeding fresh fish, frozen shrimp, blood worm as well as pellets up until yesterday when i routinly cleaned his tank, now he is hiding as if scared, not feeding and has no personality.  He wont come out of hiding even when live food is swimming around in front of him.  What can you sugjest i do to make my little friend happy again.
David.

Answer
Hi David,
Oscars must have big tanks.  One Oscar needs 65 gallons of water all to himself to be healthy, and happy.  Two Oscars you must double this, and so on.  You did not mention the size of your tank, so I do not know how you are keeping him.  Oscars kept in small tanks will have stunted growth.  Their internal organs have no place to grow, and they die a horrible death.
You must find out what is stressing him.  I do not know, you are the only one who can figure this out!  It takes observation.
I also want to mention that feeding Oscars feeder fish is not good for them.  Feeder fish are mostly always full of disease, and if eaten by another fish, they in turn will be sick.  They also have no nutritional value.
Here is a list of food that Oscars should have:
Frozen veggies ( peas, green beans, broccoli, and carrots)  Blanch the veggies, and let cool before feeding them to your Oscar.
Earth worms - buy them at the bait store, and clean them before feeding them to your Oscar.  To clean the worms put them in oats for about a week.
Frozen fish that come from rivers, and lakes.  They must be frozen, and the must come from rivers, and lakes, and NOT salt water.  Unfreeze, and feed them to your Oscar, he will love this.
Fruit, such as mangoes, and bananas, now, and then...NEVER citrus fruit.
Crickets that you buy at the pet store.
A good quality flake, pellet, and sticks.
Oscars, as well as other fish must have a varied diet.  Peas are important, and should be fed once a week.  On the day you feed him peas, feed him nothing else so he can clean out his system, and avoid Swim Bladder Disease.  
An Oscar to be happy must have a big tank, varied diet, and clean water free of ammonia, and nitrites.  Since he is stressed, you must try to find the cause.  He may be sick, or it may be because of other fish in the tank.  You must try to find out the cause.
I hope this will help.
Lynda