Well If it gets too big before I can save up for a tank, then I'll have to take it back. I'll have to ask them if they will take it back if I can't get the required tank size.
it wont get to big that fast, it will be ok for a couple of months if you wish, but it will become a strain on you doing every 2nd day water changes, upgrading a filters etc, the faster you can get that tank the better.
Dont do it. Temporary tanks rarely work out as being temporary and you could find yourself either stuck with a large fish in a small tank or having to take a fish that you really like back to the store. Wait until you can afford a tank of at least 75 gallons before buying a oscar or any other large growing fish.
The only way I can afford the 70 or 75g tank is if I wait until my birthday (01/11/05) and in january the shop I goto put in the oscar tanks scats instead. Then the only time I can get an oscar is in the late spring/early summer.
I'd back CFC on this one. The temptation to say "it'll only be temporary" is too great and that tank you are getting next month turns out to be 3 months, then 6 and so on.
If you can honestly say that a new tank is definately coming that will house the Oscar for life (and I agree with the earlier post that a 55g is not big enough. IMO a 75g is min for one Oscar) then it would be OK in a smaller tank for a couple of months, but they grow fast, so make sure that new tank comes sooner rather than later as you'll be gutted if you have to give him up because they are great fish!!