At least how many inches does Oscar fish grow in a 5 gallon tank?

Answers:
Contrary to popular belief, the size of the tank does not stop a fish from growing. An oscar, if kept long enough, and if it were to somehow survive such a microscopic and, eventually, toxic environment, would still grow to its full adult size of 5 to 12 inches, depending on the species. But, the thing is, if a poor oscar were forced to live in a 5 gallon tank for very long, it would simply die because it just couldn't survive in such a tiny, tiny toxic tank.

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The Oscar fish should never live in a 5 gallon tank. They will get upto a foot long. You need atleast a 55 gallon to keep him in.
And in a 5 gallon tank he might grow a couple of inches but he needs his space so move him to a 55 gallon tank. Hope i was helpful

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Any Oscar in the world is capable of growing 12 inches. The larger males can grow past 16". It will grow to about 4 or 5 inches in that tank and soon after will die, murdered by an ignorant fish keeper. You keep asking all these questions about Oscars in tiny tanks. Here's your answer for all of them:
NOTHING LESS THEN 40 GALLONS FOR A SINGLE OSCAR, PERIOD.

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None ,he will die before he gets a chance to grow.If you really want an oscar save up and get a good size tank( 50 gallons) for him.