I'm french, so I apologize for my english...
I bought 2 canary last week (one female and one male). Yesterday morning, the female became fat (like a little ball!). The feather were ruffled. Finally, it was dead at the end of the afternoon. Just a few minutes before this dramatic issue, it was lying on the floor. The breathing was difficult.
Yesterday afternoon (the same day!), my male became fat too. The breathing was difficult.
This morning, the male looks better (breating less rapid, less fat). But it still bad...
I 'd like to know if someone knows this disease and where the problem is. Might it be possible that I bought ill canary? Might it be possible that I did something wrong during the week before the death?

I 'm new with canary birds. I find them interesting but I'm sad... Please help.
Here is a site with a lot of info about canaries.
http://robirda.com /
Take the bird to an avian vet immediately, and hopefully they will tell you what's wrong, and cure the bird. Birds instinctively hide their ilnesses until they are too sick to do so anymore. Once you notice, they are very sick. If you wait any longer, the bird will likely die.

it sounds like you have something toxic going on in your enviroment. do you have these birds near the kitchen.
you need to get the male to a vet if it dies have the vet post mortem the bird so you can find out what killed it