One of the best algae eaters are Otocinclus catfish. They're cute little fish and like to be in small groups. They don't grow to be more than an inch long and like to hang out on leaves of plants. Depending on your tank size you might need quite a few. Obviously it depends on the amount of algae you have in your tank as well. I would estimate that you might want about 2 or 3 for every 10 gallons. Traditional Chinese Algae Eaters only eat algae when they are young. I've never found them to be very effective.