Algae is a nuisance for those who possess fish tanks. If they grow unrestrained, algae can suffocate the fish to death and also deteriorate the ecosystem of the aquarium. You can control the growth of algae in many ways, but it would be beneficial to add some fish, which feed on algae. There are many algae-eating fish like the Chinese algae eater, Siamese algae eater, American-flag fish, and catfish of South America (like Otocinclus and Plecostomus species), bristlenose catfish and some freshwater shrimp like Amano shrimp. Nowadays, they are sold as 'algae eaters.' Some species of algae eaters feed on specific algae only, but some others eat more than one type of algae. Plecostomus or Plecos Plecostomus or Plecos (Hypostomus plecostomus) are very popular as algae eaters as they can clean tanks by eating algae. These fish are available in small sizes (3 or 4 inches of body length), but they can grow up to two feet and this makes them ideal for very large aquariums. These fish are very aggressive and may sometimes eat smaller fish in the aquarium and even the aquatic plants. Hence, it is necessary to supplement their diet with blanched romaine lettuce or spinach. If your fish tank is small, you can go for the bushy nosed pleco or the suckermouth catfish, which are smaller. They feed on the soft green algae from the rocks, logs, and the glass of the tank. Sometimes, they may eat small aquatic plants too. Otocinclus Cats This algae-eating fish is a genus of catfish, commonly called Dwarf Suckers or Otos. They feed on a variety of algae and prefer to move around in groups. It is difficult for them to survive, if there is no algae in the aquarium. In such situations, the only way to help them out, is by supplementing their diet with blanched cucumber. They remain small, so are ideal for small fish tanks. Make sure that you keep them in a group of six or more. If you have this fish in your aquarium, you have to keep the aquarium as clean as possible and check the water quality regularly. Siamese Algae-Eater The Siamese algae eater (Epalzeorhynchos siamensis or Crossocheilus siamensis) is a fish with a black horizontal band, which runs through the entire body length. They lack the maxillary barbels found in fish being sold in the name of Siamese algae eater. The popular fish sold as Siamese algae eaters are actually distant relatives of this fish. They are Crossocheilus langei, which are otherwise known as the red algae eater. This fish has a brownish black body with a black band extending from the nose to the tail. They can grow up to 16 centimeters and possess small maxillary barbels and a slightly arched upper lip. They feed on red algae, hair algae and beard algae. Japonica Shrimp Japonica shrimp or Amano shrimp (Caridina japonica or Caridina multidentata) is considered as one of the best algae-eating shrimps and is used widely in aquariums. They feed on black brush algae, hair algae and the normal soft green algae. Japonica shrimp has a translucent body with very small reddish-brown spots, which is aligned like a broken line. They are also characterized by black eyes and a white stripe on the dorsal part of the body, which extends from head to tail. They are nocturnal and these small creatures may fall prey to larger fish in the aquarium. Copper-based water additives or medicines can turn fatal for these shrimp, so avoid using such products. Other than these, there are many other species, which are used as algae eaters. They are black molly, butterfly goodeid, Florida flag fish, rosie barbs and twig catfish. You can choose from this broad range of algae eaters, as per the size and requirement of your fish tank. You may also go for a combination of algae eaters to control the growth of different types of algae. Adding algae-eating fish can accentuate the beauty of your aquarium as well as help in controlling the growth of algae.