Rosy Barbs and American Flag Fish are a couple of the showy tropical algae eaters. The male Rosy barb has a brilliant metallic sheen that shimmers from red to gold to green as it darts through the water. The female is more subdued but still has wonderful green gold hues. The American Flag Fish has a stunning red and blue striped pattern for which it is named. Each of these varieties will eat most green and brown algae – though the barbs will start grazing on your plants if enough algae is not present.
Siamese Algae Eater | Tim's Tropical Fish
Hello Tammy, How “small” is this tank? Two goldfish should have at the very least a 20-30 gallon tank even when small to handle the waste they produce. If your tank is any smaller, I would not recommend adding anything else to it. If the tank is over that size, snails would be your best bet since other algae-eaters like those discussed here are tropical fish and would need warmer water than goldfish.
7 Best Freshwater Aquarium Algae Eaters | Home Aquaria
Many freshwater tropical fish are great algae eaters in their own rite. Livebearers including Black Mollies, Fancy Guppies, Platys and swordtails eat string algae and sometimes white beard algae. Guppies and Endler’s Livebearers also do a number on the green algae in a tank. With their prolific breeding habits these little guys will have their fry invading every possible algae hideout. Another great tropical algae eater is the Siamese Algae Eater -- how could it not be with a name like that. This cigar shaped fish sports a black horizontal stripe down the length of its body and readily consumes green, brown, red, white and even the dreaded black fuzz algae. This all purpose cleaner is a must have for 55 gallon and larger tanks. The Siamese algae eaters grow to about six inches and like to shoal in group of three or more so smaller tanks aren’t a good fit (although having just one in a 29 gallon tank has worked for me in the past).
Tropical Fish for Freshwater Aquariums: Chinese Algae ..