cockatiels and galahs

Question
can i have a cockatiel and a galah in the same cage?

Answer
No!
Cockatoos can be very aggressive at some points, they being much larger than cockatiels. One bite from a galah on a cockatiel can kill your cockatiel. Keep them in separate cages next to each other. If they are together, I would keep close attention on both of them.

Hope that helps ;)