x2.. Oscars are cichlids.. cichlids are territorial unless you get lucky and all 4 are the same sex you're going to have aggression issues. and if you get a pair.. you can say goodbye to the other 2. Once they mature they'll get aggressive. imo your best off keep 1 you really like and taking good care of it. or lett them pair up and remove the 2 unpaired. BUt you still are liekly to have aggression issues with a pair in such close quarters.
right now I have 4 baby tiger Os in a 100g tank. will this be big enough when there are fully grown