It all depends on where you live and how you obtained the BTC.

Where I'm at if I'd just bought it then no. If I got it by earning it and trading if it's above the limits they give then I'm still liable for the tax on those earnings even if I have no way of paying it.

Look at these people who did a million shitcoin trades, wound up with nothing and didn't realise every trade was taxable.

Still, I wouldn't bother mentioning it.