Damselfish are small, colorful marine fish belonging to the family Pomacentridae. They are commonly found in coral reefs and rocky areas in tropical and subtropical oceans. These fish typically measure between 1 to 6 inches in length and are known for their vibrant colors, which can include blue, yellow, and orange. These fish are often territorial, defending their nesting sites from intruders. Damselfish primarily feed on algae, plankton, and small invertebrates. They play a crucial role in maintaining the health of coral reefs by controlling algae growth, which can otherwise overwhelm coral ecosystems.