oscaroo .......... if'n I was you, I'd quit planning on tanks that you don't have, and quit listening to the minority.
Also, IMHO, a 75 gallon isn't an ideal long term tank for an oscar either. It's better than your current tank due to the longer length, but IMO is still far from ideal for an adult O.
The ultimate irony is that I see you are already giving advice to other people about min tank sizes, and the fish they should keep. What you should be doing is spending less time posting on forums, and more time reading, researching, and learning about what works, and what typically doesn't. Most experienced oscar keepers would never recommend keeping an oscar long term in a tank the size of yours. In the end you will have a far better experience in this hobby if you start small, and work your way up to monster sized fish. Here's a place that you may want to start with your research.
http://www.oscarfish.com/
well I messed up converting the sqare inches into gallons and found out it was a 65 gallon. PS my 65 gallon is 18 inches deep witch gives him plenty of room to turn around in
my 55 gallon is not a standerd 55 gallon. it is deeper and taller than a standerd 55 gallon and is about 2-2 half feed long
Best case scenario this tank is a 65 gallon, worse case scenario it's a 50 gallon, either way it sounds like it's only 36" long, and 18" wide. Just so everyone is on the same page as to what size this tank is.
plecostic .......... previously you stated;
Best advice is to to be realistic about your fish keeping goals. It's perfectly fine to keep oscar in a smaller tank, once they out grow it, you can always upgrade and use the smaller tank for other fish or whatever.
Which I think was very sound advice. Considering this fish is most likely the OP's first fish, and first fish tank, and certainly their first oscar, do you really think that encouraging a fish that has the potential to reach 16", and produce a ton of waste, being kept in a tank this size for its entire life, is being realistic? I see oscars being returned to LFS's in my area on a regular basis, and it is almost always due to the fact that the owner is a young person, with little fishkeeping experience, and who got in way over their head. Too large of fish, too small of tank, and too much work to keep the water parameters stable. In the end the fish suffer, many become sick (such as the OP's fish) and some die before even having the option to rehome them. I've seen enough oscars with severe HITH to last me a lifetime.
I don't see your advice as being realistic, I see it being very unrealistic, as most people new to the hobby are not disciplined enough to pull this type of a set up off successfully. This is why I cringe when I see stores such as PetSmart selling cute little juvie oscars, pacus, etc, as realistically I know that the vast majority of the fish purchased at those stores are going to end up in the hands of someone that has no idea what these fish require over the long haul.
Either way I'm not going to go round & round attempting to tell anyone what they should, or should not do.
With any luck oscaroo will take some of the advice that has been given here & become a better fishkeeper for it.
Cheers
