Canaries main seed is - naturally enough - canary seed, but they also need a mix of milletts, and if you want your boy to whistle his little head off at the correct time of year.
Canola/rape seed is the perfect aphrodisiac that will get him singing. Being a form of finch, they also need greens. Idealy green seeding grasses. Fruit is not natural to them, but some like apple.
Only replace his seed when it is down to 1 or 2 types. Canaries are generally an easy bird to feed as they are so curious they will try almost anything. So caution is needed, because this will include what is not good for them, or only good for them in small quantities, like too much fatty seeds. (in this canaries are like some people, no healthy boundaries) Hemp, sunflower and safflower are good, but in tiny quantities or he will get fat and die of fatty liver disease, and that would not be good for him or you.