Hi there,
Yes - you must pay taxes on gains from these altcoins. It is no differnce than buying/selling commodities and there is a risk that if you trade frequently, it can be considered a business and 100% taxed at your marginal tax rate. Here is a link:
Here is a link: https://www.canada.ca/en/revenue-agency/programs/about-canada-revenue-agency-cra/compliance/digital-currency/cryptocurrency-guide.html
In terms of can they track? They absolutely can and the CRA part of a multi-government consortium dedicated to just this. They also introduced legislation to ensure that all crypto platforms that intend to operate in Canada sign up with IIROC.
So yes, you should absolutely be aware of the tax implications. Beyond that, you should talk to an accountant or ensure you educate yourself on the intricacies.
Mat