Fish, snails and other animals do eat algae… so the thought that if you have algae, and its overgrown to an undesirable size or shape, adding algae eaters to attack the plant matter is in theory… a good idea.
Unfortunately, the appetite of most animals won’t tackle the weeks/months/years of algae that may have accumulated in a tank. So, adding some grazing animals will help maintain a healthy tank, but don’t expect them to fix an outbreak or pre-existing problem. Physical removal, such as picking with fingers or trimming with scissors and then sucking out through a hose can be the most effective way to address an algae overgrowth/bloom.
More frequent nutrient exporting can help reduce the rate of growth while grazers can help manage the growth. Every ocean should have a balance of predators and prey.
A few animals that will help maintain hair algae