Chrysiptera parasema, also known as Yellowtail Damselfish or Goldtail demoiselle 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 three inches in length. It is blue with a yellow tail.

In the Aquarium

Chrysiptera parasema 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.

It is less aggressive than most damselfish but will sometimes harass more passive fish. Despite its comparatively peaceful nature it can be territorial with members of its own species. This aggression can sometimes be reduced by keeping them in groups of three to seven. They do show schooling behavior when kept in large groups. Despite its 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.