LOS ANGELES – Another day, another new bank fee.

As the uproar swelled over Bank of America Corp.’s planned $5 monthly charge for debit card use, megabank rival Citigroup Inc. was notifying many Citibank customers that they soon would have to start paying for their checking accounts unless they maintained significantly higher balances.

Letters are going out across the country alerting Citi customers of account changes, said the bank’s retail banking chief, Stephen Troutner.

In many cases, that means customers will have to maintain fatter balances to avoid fees, although Troutner said a basic account option makes dodging charges easier.

Higher fees are the new reality in retail banking, where regulations adopted in the aftermath of the bank bailouts have reduced revenue from several controversial fees by billions of dollars.

At the same time, banks have seen their lending income decline because of the sluggish economy and low interest rates.

That has caused major banks to impose a variety of new customer fees, although the exact formula varies.

Citibank, for example, decided not to impose “usage” fees such as the $5 a month that Bank of America, starting next year, will charge most customers who use their debit cards to purchase goods and services.

“We conducted extensive surveys with our customers, and no one wanted to pay to use debit cards,” Troutner said.

One day after announcing the new debit card fee, Bank of America was inundated with visits, calls and emails from customers.

“We are doing our best to explain the impacts, the value and convenience the debit card offers and how to avoid the fee if necessary,” spokeswoman Anne Pace said.

Short of taking out a Bank of America mortgage or depositing $20,000 with the Charlotte, N.C.-based bank, the way to avoid the fee is to avoid making purchases with debit cards and using them only for ATM transactions, which remain free.

The troubled bank, already besieged by multibillion-dollar lawsuits and massive financial losses, saw its stock fall 3.6 percent by the close of trading Friday.

The shares have plunged almost 44 percent for the quarter; for the year, the stock is down 56 percent.

Now the bank faces a public relations backlash.

The debit card change has sparked fury on the Web and cable news channels.

Consumers complained on message boards and in social media, vowing to take their business elsewhere.

Fox Business Network’s Gerri Willis went as far as to cut up her debit card on the air Thursday evening, The Washington Post reported.

“Right here, right now, I’m going to show Bank of America what I think of their fees,” she said, using a pair of scissors.

Bank of America also was hit Friday with online banking problems that knocked out service on the East Coast for more than two hours, spokeswoman Tara Burke said.

Burke wouldn’t describe how the outage occurred but said it was not caused by hackers or related to the uproar over fees.

In imposing the new fees, the big banks are “playing with their futures,” said banking customer-service consultant John Tschohl of the Service Quality Institute.

“When you become arrogant and start acting like a monopoly,” he said, “it will come back to haunt you.”

The Washington Post contributed to this report.