Cuttle Fish Bone Minerals:-
Your cute and cheerful parakeet gets most of the nutrients he needs from a balanced diet of seed and fruit, but he may be lacking in certain minerals. Calcium, which helps your bird's bones, beak, toenails and feathers stay strong, isn't commonly found in at high levels in a parakeet's typical diet. While fruits and vegetables can be a source of calcium, many parakeets tend to pick and choose which foods they will eat, which can lead to deficiencies. Cuttlebones are an important source of calcium, as well as other trace minerals your bird needs.
Beak Maintenance
When your bird rubs his beak against the rough surface of a cuttlebone, he's helping keep himself groomed. The cuttlebone grinds away the outer layers of the beak, leaving room for growth. An overgrown beak can be problematic because it can make eating difficult, which can lead to malnutrition. While your bird scrapes away at those dull outer layers, he's also exercising his jaw.
Concerns
A cuttlebone is a natural product and isn't actually a bone at all. Instead, it is the inner shell of a squid-like cephalopod called a cuttlefish. Some people worry about contamination in cuttlebones, but according to the Humane Society of the United States, cuttlebones are safe for birds to use. If you are a vegetarian and prefer that your bird not consume animal products, you can use a mineral block to supplement his need for calcium instead of a cuttlebone.