also known as Chrysiptera parasema, is a popular and hardy marine fish species found in the Indo-Pacific region. They belong to the family Pomacentridae, which includes a diverse group of small to medium-sized reef fish.

Yellowtail Damselfish are relatively small, typically growing up to 8 cm (3 inches) in length. They have a deep, compressed body shape with a pointed snout and a single dorsal fin. Their bodies are primarily blue with a bright yellow tail, which distinguishes them from other damselfish species.

In the wild, Yellowtail Damselfish inhabit shallow coral reefs and lagoons, often in large groups. They are territorial and will defend their space against other fish and intruders. They primarily feed on small crustaceans, algae, and plankton.

In the aquarium hobby, Yellowtail Damselfish are a popular choice due to their hardiness and bright coloration. They are relatively easy to care for and can adapt to a range of water conditions. They are also very active swimmers and can be entertaining to watch.

However, it is important to note that Yellowtail Damselfish can become aggressive towards other fish, especially if their territory is invaded. They may also nip at the fins of slower-moving tank mates. Therefore, they are best kept in larger aquariums with plenty of hiding places and other active fish species.

In terms of feeding, Yellowtail Damselfish will readily accept a variety of prepared foods such as flakes, pellets, and frozen foods. They should be fed multiple small meals throughout the day to ensure they receive enough nutrition.

Overall, Yellowtail Damselfish are a popular and attractive addition to marine aquariums. Their hardiness and ease of care make them a great choice for beginners, but their territorial behavior and potential aggression towards other fish should be taken into consideration when choosing tank mates.