Crypto tax - self-assessment?

Hi there, few years ago I did send some money from my bank account to exchange to buy some USDT to start buy/sell crypto tokens. There were months in the past when I had tokens which value was more than I have originally sent from my bank to exchange, there were months when value was less. At the end I still have tokens (USDT and other) and have never sent any £ back to my bank account or any other bank account. In my situation should I register for self-assessment please?

Hi,

You can find guidance here:

Self Assessment tax returns

Thank you.