I have been looking through the import laws and came upon this:
Importation of Aquatic Animals
Aquatic Animals not Listed in Schedule III
194. No person shall import an aquatic animal that is not listed in Schedule III unless it is accompanied by a document that is satisfactory to an inspector and that includes the following information:
(a) the name and address of the exporter;
(b) the name and address of the importer;
(c) the taxonomic name of the aquatic animal, the life stage, and the number being imported, if more than one; and
(d) the country in which the aquatic animal was born or where the germplasm came from and, in the case of an aquatic animal, whether it was born in captivity or in the wild.
SOR/2010-296, s. 4.
Ampullariidae, Pilidae, Pomacea are NOT found in Schedule III
Therefore to import apple snails into Canada all that is needed is name and address of importer and exporter and taxonomic name and country of birth!

WeeSnail - Adele - “Learning is not compulsory... neither is survival." - W. Edwards Deming (1900 - 1993)