I know this thread is old, but I can't believe I missed this completely,nor that anyone corrected it when said, and I sure hope this was sarcasm when it was, therefore I'm going to correct it so others that read this aren't mislead. Oscars grow very quickly, and the debate whether or not a 55 or 75 would suffice as bare min for life goes on (75 gives extra width), so in no way would a ten gallon work, unless it would only be for temp. housing/grow-out. In other words, just like in the snake world, where bps are probably the most abused when it comes to proper husbandry, the same is true if not worse for oscars in the fish one (along w/pacus and iridescent sharks).I have my oscar in a 90, and hes going into a 220, I know that is more than adequate, but I love my fish like most of you do your herps. So please please please, never buy an oscar with plans only to keep in a ten, although seeing how they act even in the stores, I can see the temptation, as most of these end up back in these stores dumped off when they outgrow their tank, or dead.