For US tax, you have a couple of transactions. First, you have the payment for your services. You will show $4,000 (fair market value of cryptocurrency received) as gross income. (See Q-3 of Notice 2014-21.)
After that, you held the cryptocurrency as an investment. Your cost basis was $4,000, and you made 15 trades on the cryptocurrency. You ended up netting $1,000, and your cost was $4,000, so you have a capital loss of $3,000. The capital loss is short-term if held less than a year.