Hi Louise,

You're cockatiel is really up there. Must be all that good care it receives!

As far as your canaries go, it's actually natural for them to fight. Let me clarify that for you.

If you've ever seen an actual canary breeding cage, it has a divider in the middle. The reason being is that until the hen is ready to accept the male, she will fight with him.
Usually she makes the nest and gets ready. When she's getting close to the breeding mode, you'll see the male feeding her through the wires of the division. That's usually when you can put them together and they should get along. She will lay the eggs and the male should feed her. He will also help to feed the chicks.
Also, you have to bring canaries into breeding mode and this is done with lighting and diet. Usually around late January to Early February, they need to have their light period lengthened. It needs to be increased daily so that when they are up to about 14 hours of light per day, they will start to think about raising a family.
The diet needs to be one that his higher in protein. They make commercial egg food that you can use. You can also serve them hard-cooked eggs blended with the commercial egg food. They also must always have oyster shell and cuttle bone as added calcium supplements. This will prevent soft-shelled eggs as well as egg binding in the female. Flax and hemp seed are also beneficial to them during this time, along with thistle or niger seed.

That's really just a mini version of how to get your canaries to successfully breed. You learn from trial and error and of course from those that are successful breeders. I no longer raise canaries, but did at one time.
I you have a canary breeder in your area you might contact him/her and see if they would be willing to give you some advice.

Good luck and glad to see you here.

Michael