Most male canaries are solitary and territorial creatures, so of course they'll fight when put together. They see their cage as their territory, so no fights happen when they each have their own cage, even if those cages are put next to each other.

I have two canaries who are both really territorial.

They used to be together when one of my canaries was around 3-4 months old and they got along fine but got sick of each other. ( during summer )

( during Autumn )

I put them together again and by them my younger canary was 6 months old and when I put them together they would just fight and because territorial or the food and perches and things so I moved them back in their own cages. They are fine next to other In different cages but not together.

Why is this?

Thanks for you help!

p.s my older canary is supposedly male.