After many hours searching online, you do have to pay taxes on EVERY trade you made profit with!! Trading, for example, BTC for ETH is the same as trading BTC to CAD and CAD to ETH. You have to pay the tax on capital gain for the BTC "sell". For now i'm not sure of the method that is recommend in Canada to determine the initial value of the BTC used to buy the ETC if you have bought/acquire BTC over the time at different prices. I have found 3 ways to do this. The First In First Out, the Last In Last Out and the average buy price. I'm not sure which one to use in Canada

... For tax, capital gain is taxes at your marginal rate for half the amount of gain which is calculate with a simple formula : Sell price minus fees MINUS Buy price with fees = Capital gain. Be aware that a person buying and holding for more than a year is consider a long time trader and the income is a capital gain. For those who trades (buy and sell) inside a single year, they can be flag as "professional trader" and the profit made on each trade is becoming like a job income and is all tax at your marginal rate!!
And now the disclaimer, I'm just a small trader and i'm not a financial/accountant professional in anyway, my personnal advise is if you want to be save, declare your income, pay your tax and keep proof of your trades as sign of good will. That way you will keep CRA far from you even if they ask you proof, send them and you will never hear from them again. To be sure always ask for professionnal help (wich is really hard to get for something virtual like bitcoin)!
Enjoy!
Edit : Here a link for a PDF made by 2 professionnal
Olivier Fournier. Deloitte Tax Law ll p, Montreal. Frequent
speaker, writer, and presenter at tax conferences and seminars.
John J. Lennard. Davies Ward Phillips & Vineberg ll p,
Montreal. bcomm (2007) Laurentian University; bcl , ll b
(2011) McGill University.
https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0ahUKEwj8n867y-vVAhVGLSYKHR5qCH0QFgheMAc&url=https%3A%2F%2Fwww.dwpv.com%2Fassets%2F-%2Fmedia%2FF28E60C148DB463DB31E0CF66008FD2A.ashx&usg=AFQjCNE-1eNUL1Mt0Kv2W7a6nhr-jyfOnQ