There is no tax until we keep using bitcoin as bitcoin but still it is not possible yet so we need to convert our bitcoin into fiat so bank is essential so our earning will be recorded so we must need to pay taxes according to our income.
There's no need for the bank to get involved with our bitcoin income. Paying tax is essential whether bitcoin isn't recognized then the only thing that we must do for declaring our tax is to volunteer ourselves going to the tax bureau and declare your bitcoin income.
They can track using the bank details, because banks may be asked to provide details if account is being open for btc transactions or any suspicious transactions happening regularly than those details will be forwarded to them and then you will be under scanner.
They can and they can't. If you use an exchange that is sending payment through banks then for sure you are obliged to pay the tax because it is recorded to the bank's system and audit.