how big will my fish get

Question
I have a 10 gallon tank and have 4 fish in it. I just purchased a Red Osar (which can get pretty big) and was wondering if he will only grow in porportion to the size of the tank or will I end up having to get a bigger tank?


Answer
It is funny you asked this, we just bought two oscars to go with the three porta caras we have in our 55 gallon tank.
When we bought the two Oscars the salesman really didn't want us to buy two, he said the two oscars and the three porta caras (which are very similar to oscars or jack dempseys) would be too much, that they all get very large and will out grow the tank.
As we were talking a man over hearing us said he just purchased a 150 gallon  because his oscars out grew the 55  he had them in.
So my answer is they will grow and grow and grow!  The good news is they are pretty slow growers so you have some time.
We have baby jack dempseys they are still very small, we have 5 of them in a 20 gallon, but for certain they will outgrow that tank and need a bigger one. Jack Dimpseys are a Cichlid like Oscars.  We have had ours for months as have our friends who have theirs in a much larger tank, they are slow growers, but they certainly are growing. :)
You don't mention what other fish you have in your tank, you may already have it overcrowded depending on their size.  Plus, Oscars tend to be mean so he may hurt your other fish depending on what they are.
Good luck!