Mutual Fund loss and Roth IRA conversion

was thinking of some tax loss harvesting.   A mutual fund has a loss.    I’m planning on rolling over my 401k and converting some to a Roth IRA.  Since the Roth conversion generates income, can that income be offset by the mutual fund (not in a retirement account) loss?

 

not real numbers, but just for simplicity - say the mutual fund lost $5000, and the 401k converted to Roth IRA was $15000…..would I just be taxed on $10000?