Have just added 2 Oscars to my 55 gal tank and the larger one is hanging out at the bottom in one corner all day. He comes up to eat then returns back to the origional spot and stays there the rest of the day. Should I be concerned? (have not had oscars in over 15 years)

Welcome to the community

okay, the only thing you have got to be concerned about is keeping two Oscars in a 55 gallon tank. 55 gallons is not big enough for two adults Oscars. No doubt they are small at the moment, they will not stay small for long and then you may start running into water quality problems and that will give you trouble.

Oscars are sometimes very shy when you add them to a new aquarium so it's not uncommon for them to be a little timid and not to move around the tank for a while. As long as the Oscar is eating you don't have too much to worry about. However, it would be a good idea to test your water for ammonia, nitrites, nitrates and PH.

What kind of filtration have you got?

have tested water levels and all is fine the filtration is a top fin 60 uses 2 large filters and has done a great job cleaning up after the messy eaters. Yes, right now both are small...am planning to move one to a 30gallon tank when he gets a little bigger.

30 gallons is about half of what you need for 1 Oscar. 55 gallons is the minimum from one and 75 gallons is recommended. 2 in a 55 maybe be ok if you've got super filters but 1 in a 30 probably wont last very long. Keep in mind these little cute fish get 12+ inches long very fast.

Hi, there.
It would be nice to know the actual readings of the tests OFL suggested.
My O grew to over 10" within a year, they grow very fast indeed.
How long has your tank and your filter been running?

since last xmas i really wanted to get back to oscars so i have all my other fish in a 20gal now and the 2 oscars in the 55 gal. did a complete water change and thorough cleaning and let it run for 3 day b4 adding the new oscars

i have to agree with the above posts, unless you already have plans on upgrading to a bigger tank, I would re home one oscar now, these guys grow super fast.

Can only repeat what has been said, a single oscar needs at least 55g, 30g is far far too small, you wont be able to keep the water good. if you keep 2 oscars in a 55g or one in a 30g then in a few months you will be posting about your oscar being sick

Dont worry about your oscar hiding, its normal for newly introduced fis to do this, he will come on in a few days or so

these two are in a 55 gallon - two months ago they were tiny babies from the petstore (about 2"). They have more than doubled in the last two months and have a lot more growing to do. When I bought them I had already committed to getting them a bigger tank. I'm running filtration that is rated for 320 gallons and doing water changes every 3-4 days.

thought a picture may help with perspective on how fast they get and how crowded they would be in a 55 gallon....