Welcome to the community!
Unfortunately, I don't think Fido will be able to offer Home Internet services in St Catharines. Since Fido is a subsidiary of Rogers, they would use Rogers' cable infrastructure. I do not think St Catherines is within Rogers Cable's territories (see here). To be sure, Rogers is not listed as an internet service provider for the area on the CRTC's Service Providers Near Me. I think it's highly unlikely that Fido would provide Home Internet outside of Rogers' territory.
Not what you wanted to hear, but hope this helps 😀