Do Tiger Oscars get mad/sullen when you add something to their tank?

My Tiger oscar was happy and normal yesterday and after I added a heater he seems withdrawn today.The water chemistry is fine and the heater is set to 78 and was 78 before I added it so there was no sudden spike or decline in the Temperature.I cant figure out why he is acting this way.I put his favorite treat in this morning which is brine shrimp and he didn't eat one and he usually goes nuts when I add them.He is just hiding and slightly tilted to one side kinda like he is sleeping.It started last night and continued this morning.I went to act like I was going to touch him to see if he was ok and he swam away lightening fast so I know nothing is wrong with him physically? Why is he acting pissed and how long will he act this way? I cant think of anything I did wrong???Please help