How do you know when the oscar fish needs more space?

Question

well he keeps moving everything in the fish tank

Answer 1

Oscars are interior decorators, by trade.  No matter how much space you give them, they will keep rearranging the tank.  

You should have a 55 gallon tank to start, and be prepared to upgrade to 100 gallons very shortly.

Answer 2

can it turn around in your tank

Answer 3

thts what oscars do...read this...they will redo all the decor they want to..let him do it..its his home..he will not like the placement of rocks as it pleases you..he will do it the way he wants it to be...thts how oscars are...you have to accept it..they are very strong...and need setups of 55 gallons or even more...when he outgrows his tank..obviously its time for an upgrade...I mean oscars really get big..research more..