You cannot, cannot house them together or let them play together. A conure is capable of killing a cockatiel with ease. They are extremely hyper and can be vicious.

 

Larger Parrots should never be housed with smaller birds. It can even be risky for them to be housed with parrots of like-species. I would consider possibly just getting your cockatiel another cockatiel as a friend if you plan to get another bird. =/

 

****. Very well, thank you very much for the answers. I am so happy that I asked it instead just buying one.
Them being hyper is the reason why I was thinking about getting one. In the pet store, all the cockatiels do absolutely nothing, just sit still, while conures were active and playing around.

 

http://talkcockatiels.com/showthread.php?t=27104 This sticky explains why not to house tiels with other birds. Tiels are pushovers and others birds can be very bossy. Conures have rather large beaks and they could do some serious damage. And trust me, how a bird acts in the bird store with a bunch of other birds that in the wild would be considered predators in way reflects how they would act in a safe environment.

 

Thats just horrible...
Its also bad that in the pet store, tiels are housed with a few budgies.

 

People don't realize that just because budgies are smaller they can hurt a tiel.

 

I have a budgie and a cockatiel.

It's fine as long as they have the option of getting away from each other.

Peeper goes in Vivi's cage sometimes to be social, but I always make sure the door is left open so one can get away from the other if need be. I have seen Vivi and Peeper make aggressive movements towards one another before, but as long as they can get away from each other, it's never led to anything, and I've seen the budgie giving the cockateil scritches <3. A budgie for a friend would be fine if you have separate cages for them and only supervised play.

I have seen budgies and tiels housed together before successfully, but it is a touch and go thing and depends on the individual birds. Not a good idea unless they were raised together or something of that nature.