Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term investors' portfolios.

Let's learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

If you are looking to diversify your portfolio, consider Gotham Total Return Institutional (GTRFX). GTRFX is a Long Short - Equity option. These funds' investment strategy consists of minimizing overall market exposure, while at the same time taking long positions in equities that are expected to appreciate and short positions in equities that are projected to decline. This fund is a winner, boasting an expense ratio of 0.87%, management fee of 0%, and a five-year annualized return track record of 11.44%.

Alger Responsible Investing I (AGIFX Quick QuoteAGIFX - Free Report) . Expense ratio: 1.11%. Management fee: 0.71%. AGIFX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. This fund has managed to produce a robust 11.61% over the last five years.

Nuveen Quant SmallCap Equity I (TSCHX): 0.45% expense ratio and 0.39% management fee. TSCHX is a Small Cap Blend mutual fund, allowing investors a way to diversify their funds among various types of small-cap stocks. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 11.02% over the last five years.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.