Chrysiptera hemicyanea, also known as Azure Damselfish or half-blue damselfish is a popular saltwater aquarium fish from the Indo-Pacific

Indo-Pacific

The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...

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Appearance

A small marine fish that reaches four inches in length. It is blue with a yellow tail and belly and is sometimes mistaken with the yellowtail damselfish which has less yellow, particularly on its belly.

In the Aquarium

Chrysiptera hemicyanea is a hardy member of a saltwater aquarium. Because of this and its usually low price it is often recommended as a way for novice marine aquarium keepers to gain experience. Thirty gallons is typically quoted as the minimum tank size required to permanently house this fish. To keep a small group a tank of fifty five gallons will be required.

It is less aggressive than most damselfish

Damselfish

Damselfish comprise the family Pomacentridae except those of the genera Amphiprion and Premnas. They can grow up to long. While most are marine, a few species inhabit the lower stretches of rivers in freshwater. Damselfish usually have bright colors. in tropical coral reefs, and many of those are...

 but will sometimes harass more passive fish. Despite its comparatively peaceful nature it can be territorial with members of its own species. It is however reef safe and will not harm invertebrates. Even though it has a hardy nature, it also must not be placed in an aquarium with larger predatory fish such as lionfish

Lionfish

Lionfish may refer to:* genus Pterois, collectively known as the lionfish* Red Lionfish , a significant invasive species off the East Coast of North America and in the Caribbean-Fish:...

, and grouper

Grouper

Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes.Not all serranids are called groupers; the family also includes the sea basses. The common name grouper is usually given to fish in one of two large genera: Epinephelus...

which will often see it as a food source.