I have 2 oscars, I got them on Saturday. So far they haven't eaten anything as far as I know. Everytime I get near the tank they hide and lay on their sides. If they think I'm not looking they swim around. Are they just being stubborn like I know they can be or is something wrong? Also the tiger does this tail flickering thing that I don't understand but the fish don't fight.

Water has been tested and its all normal. I don't have exact numbers right now cuz I didn't write them down but I will get them up soon.

any ideas?

Were these oscars introduced to a brand-new tank, or has the tank been set up with other fish in?

The behaviour you described is certainly fairly common with the new fish that have been introduced into an aquarium. Give the fish a little bit of time, maybe leave the lights off for a little while to let them settle in.

However, you really do need to test the water again and give us the results. From what you have said, it sounds like you haven't got any test kits yourself, I would strongly advise you to get some because you never know when you will need to test the water.

By the way, how big is the tank and what type of filtration have you got?

Tail shaking is how I think fish communicate with each other. Some people have suggested that it is actually aggression, I dismiss this because my fish do this quite a lot and they are perfectly friendly with each other, in fact I have four Oscars and they have split up and formed two pairs, or so it seems anyway.

My results are( since yes I do have test kits). Just out of amonia kits at the moment but am confident of my tank.
Nitrate 5
Nitrite 0.1

Its a cycled tank that was set up previously with 2 oscars that got moved to a bigger tank then got bullied by my big cichlids and died. So the tank is fine. I am quite sure right now that my fish are just being shy. Since they just wolfed back a worm! Lol! They swim around when nobody is near the tank but as soon as we get near them they go to the bottom and lay on their sides together. How do I get them used to us being around the tank?
I'm unsure of the size but I'm getting a bigger one next week. Its not small but I want a bigger one! Who wouldn't? Lol! There is no fighting going on. The bigger one seems quite protective of the little one and they were alone in the store for a few months. I'm pretty sure they are just timid I can see them right now and they are swimming around. Such behaviour! Lol!!! Great fish!!

OFL is right, they are just adjusting

I put mine into a new tank(been running for around 5 weeks) and he sulked for about 8 days, and i was starting to worry, instead of giving him back i thought id try one thing and i turned the aerator off, turns out, he didnt like having it on, and now he is full of beans. tempramental little sod, lol

arnent they just some pouty little things??? I love mine for that. When I used to do water changesm they would lay at the bottom and pout for hours, now they try to see what I am doing, its pretty inquisitive for a fish to behave like that!