Can I still deduct a capital loss if I have no gains at all this year?

Yes. If your capital losses exceed your capital gains, or you have no gains, you can deduct up to $3,000 of the net loss against your ordinary income each year ($1,500 if married filing separately), per the IRS. That's a real reduction against wages and other income, not just against investment income. Any loss beyond the $3,000 annual limit carries forward to future years indefinitely, keeping its short-term or long-term character. There's no expiration on the carryforward, but it does end when you die; it can't be inherited. So harvesting losses is useful even in a year with zero gains, since you get the $3,000 deduction now and bank the rest for later.