my Oscar is laying on the bottom of the tank and isn't moving anymore than the current moves it. just got this one today... h2o is at good levels. temp is 77f. alone in the tank... plenty of room.

When you first put an oscar into a new environment (a new tank) they often hide and it can take a couple of days for them to get used to your tank

Another reason may be water quality, did you cycle the tank (check front page of this site if you dont know what cycling a tank is about). Can you post test results for ammonia, nitrite and nitrate. If you didnt cycle the tank then do a 50% water change now! Then do daily water changes until your tank has cycled

don't worry when i got my oscar he hid for about a week. he only feed when i was not looking.

im using a test strip to check h2o.
from what this tells me...
nitrate ppm (mg/L) is between 0 and 20
nitrite ppm (mg/L) is between 0 and .5
hardness (GH) ppm is SOFT
total alkalinity (KH) ppm is between 80 and 120
pH 7.8-8.4

the ph is bouncing from bad to good then back to bad. what should i do.

Do a 50% water change now!!!!!!!! This will reduce your nitrite and ammonia levels by half

Ok first you need to read the section on the home page of this site about cycling.

In a tank that is cycled you have bacteria living in your filter that turn fish ammonia (all animals excrete ammonia- its what makes your pee smell) into nitrite and then other bacteria turn that into nitrate. Ammonia and nitrite are posionous to fish. Nitrate is also poisionous to fish but only in high concentrations (Your weekly water changes keep the levels down). With a tank that is cycled you should have no ammonia or nitrite present

You have 2 choices. You can return your oscar to the shop,

or you can do daily water changes (about 20%) until your test results for ammonia and nitrite are zero. During this time feed once a day what your fish will eat in 1 minute and no more

Those test strips are not very accurate and dont last very long before they start to give false readings. The best way to test your water is to use the liquid bottles, they are more accurate and last a long time

How big is your tank and how long has it been running for

35 gal... been running for about two weeks with little tetras in it. took tetras out.. did 50 percent h2o change yesterday and got oscar 2 hours ago.

aaahhhhhhhhh

Your tank isnt cycled. To cycle a tank usually takes about 6 weeks or so. I would do a 50% water change now followed by daily 20% water change until your nitrites and ammonia are zero

Get yourself some liquid test kits

You can also buy something to add to your tank called prime. It changes ammonia into something less toxic (but will still show on a water test for ammonia) but the bacteria that you need in your filter can still live on it. This will help your oscar. If you use this then dont do any water changes until your test for ammonia is zero

Your tank is not big enough for 1 oscar. They get massive. You should be looking at 50g minimum, some say 75g. Oscars grow quick so start thinking about getting a bigger tank now

i had the same thing happen to me. just got a tank, let it run for a week, and bought some fish... knowing nothing of oscars, except for what the people at petco told me and what i had heard through relatives who kept some more than 20 years ago. big mistake.
i bought two approx 2.5" tigers from petsmart, let them float for about 30 minutes in the store's bag and then released them. they lost all color, went straight to the bottom and teetered there, being pushed by the current.
assuming they were going to die, i went to petco and bought 2 more (i know, dumb, ignorant and irresponsible decision). when i got back, low and behold the other 2 were swimming around. so i had 4 babies in an uncylcled tank large enough for half an adult. the two smallest eventually died, i found this website, and re homed the third leaving only one, who is still alive and growing thanks to the info obtained here.

point of the story... you aren't the first to do this, and your fish will be fine as long as you listen to the guys and gals on this forum.

you've been covered by delboybully. i could only add "do not
clean your filter assembly for the mean time until the good
bacteria establish their colony. feed them sparingly to lessen
the bio load.

at 35 gal tank, what is the flow rate of your filter pump....
it plays important role in keeping your water in good condition.