Salpa is a genus of marine fish in the family Centracanthidae. They are commonly known as porgies or seabreams. Salpa species are found in temperate and tropical waters, and are known for their distinctive body shape and coloration.

Salpa species have elongated bodies with a deep and compressed shape. They are usually silver or white in color, with some species having dark markings or stripes on their sides. They have small mouths with sharp teeth, which they use to feed on small invertebrates and plankton.

These fish are often found in schools or shoals, and are known for their migratory behavior. They can form large aggregations and swim together in a coordinated manner. Salpa species have a unique swimming mechanism, where they use jet propulsion to move through the water. They have a muscular body and can expel water forcefully from their body cavity, allowing them to swim rapidly.

Salpa species are important in marine ecosystems as they serve as a food source for larger fish and marine mammals. They are also sometimes caught by commercial and recreational fishermen for their meat, which is considered to be of good quality.

Overall, Salpa species are fascinating marine fish known for their unique body shape, coloration, and swimming behavior.