Yes, we have short term gains and long term gains, similar to wherever your from. Short term is less than one year you'll get taxed on realized gains. Long term is if you withdraw after a year you'll get taxed (less than short term taxes). I'm not sure what the percentages are.
The way to get around this is if you move to an island called Puerto Rico (hoooooo).
BTW... just googled Seppo, you dirty bogan.