Check
here if possible. It seems to indicate that fish (with the exception of puffer fish and Chinese Mitten Crab (?!) are permissible.
The Canadian Customs website states that: "Meat and dairy products, nuts, plants, fruits and
live animals, if allowed into Canada, may require permits issued in Canada in advance, and/or certificates from the country of origin."
Also, check with the airline ahead of time to make sure they allow it.