who says they know what size they get to all we do is informing them of what they will face in the future.
if they do know what has been told then there original question is answered anyway and if they don't know then they can take this additional information onboard to plan for the future.
and looking by your sig your going to need a tank upgrade aswell. 75G is the bare minimum for a oscar.
Who cares how big the oscar will get years down the line? I know how big my oscar is now: 5". I know about how fast mine grows in a year: about 3~4". I got another year or two, about, before I have to get rid of the oscar, so what is the problem? Are you saying he will get to be 13"+ in a few years, so I can't keep him in a tank his size now? Everyone is not just telling ppl what size they will be eventually, they are saying "the fish will get to be 13 inches so you shouldn't keep it." I can get you direct quotes to illustrate this point if you'd like.
Ppl, don't be foolish and get an oscar if you only have a 10g. You would only be able to keep him for a few months. What is wrong with getting an oscar and putting him in a 10g, if you're gonna move him to a bigger tank later on?
You know when it is too big for the tank by when the fish turns facing you, his tail comes close to hitting the back of the tank. Then you give it to a well respected lfs. Also, monitor it's rate of growth.
Please explain why it is unethical (or whatever) to keep an oscar in a 55g until it gets to around 8-10". Also, please explain why you can't keep a pictus cat, that will grow to 6", in a 10g until it grows to 3" then transport it to a tank with it's big brothers/sisters?
I don't know about the rest of you with cichlids, but before I introduce new fish into my cichlid tank (after the old ones are too big and... dinner. j/k) I have to get the fish to atleast 3" otherwise they get eaten. So I have to have a raising tank: a 10g. I even kept an oscar in there for a month or 2 (pauses for the quick intake of breath from everyone) before moving it to a 55g. From what I've been reading here, what I do should not happen. Noone gives any reason why you can't keep a 1" oscar in a 10g. So let's hear the reasons. Why can't you keep a 1" fish in a 10g tank? Just cuz moving is stressfull? As long as you don't move them monthly, what's the problem with moving them?