My oscar looks really uncomfortable in my 75 gallon tank. He just stays in one corner and goes up and down side to side against the glass. I have changed the rock layout to try and make him feel more sucure in the tank. The jewel is the same. They are in a 75 gallon with a bn pleco, 3 jd's, and a texas that seems to torment the jd's but not the oscar. what can i do to make him look more comfortable.