Crabs
Crabs are exceptional algae eaters. For example, the emerald mythrax will not only reduce bubble algae, he will act as a nighttime cleaning crew by spending his nights devouring leftover food. As his name suggests, he has a green body. He’s a bit clumsy, so make sure tank items are secure. Another first-rate algae eating crab is the scarlet hermit. According to Aquariums Life, this red crab is the most popular choice for maintaining a healthy level of of algae. Although he prefers meat, he will also rid your aquarium of red, green, brown and green hair algae.
Urchins
Urchins are unusual creatures who will add an interesting twist to your aquarium. The pincushion, blue tuxedo and globe urchins come in vibrant colors. They are certainly exciting to look at, but FishChannel.com recommends them due to the fact that they eat a variety of algae, such as green, red and coralline algae. However, without enough algae to eat they will go after corals and invertebrates. They are also prone to knocking over rocks, so be sure your formations are secure and stable.
Fish
Saltwater fish who eat algae are another choice. You might consider angelfish, blennies or tangs. The angelfish and tang are smart additions because they will nibble constantly on green algae. Meanwhile the blennies are outstanding due to their ability to eat both red and green algae without damaging decorations. Keep in mind, saltwater fish cannot live by algae alone; they must also be fed an appropriate diet recommended by the breeder.
Snails
Snails don't take up much room and are a good choice if your tank is getting full of other marine life. There is a variety to choose from including the trochus, nerite and abalones. Not only will they keep the sides and floor of your aquarium clean, they won’t nibble away at your corals. In fact, snails are such a safe choice that according to FishChannel.com, they are “the best all-around algae eaters for the reef aquarium.”