how do you know if your oscar is male or female?

Answer 1

oscars are very difficult to tell the sex but they say when a oscar reaches it's adult size the females are smaller then males

Answer 2

A Well the simple answer is... You don't. Oscars are very difficult to visibly sex through external features; even people who claim to be good at it have dismal track records when put to the test. The only sure way to do it is to look at the fishes vent, which is the sexual organ located directly behind the anus. In females it is larger and rounded, while in males it is smaller and pointed

try this web site
http://www.worldcichlids.com/faqs/oscarfaq.html#Anchor-Ho-28754
hope this helps

Answer 3

you don't just name it Oscar and get on with your life.