If posting tiered rates on the internet, do I need to say on each tier that fees will reduce earnings if I'm clearly stating a minimum balance to earn the APY and if that balance is maintained there are no fees? The fee would only be charged if the balance falls below the lowest tier.

The statement that "fees may reduce the earnings on your account" only has to appear once in the ad. It need not appear next to each tier in a tiered rate ad.