If I invested 30k in Ethereum and when my investment goes up to 60k, and I sell 30k just to get my initial investment back, will I be taxed on that? I live in the United States and just bought Ethereum this year.
In each country the regulations and taxes for different things are different mate. If you are not sure what to do, you better consult a professional accountant.
This can save you a lot of headaches and even tax trouble, which are very sensitive to the crypto world these days.