Blue Assessor

General information

The Blue Assessor (Assessor macneilli) is a small saltwater fish that is popular among aquarium hobbyists due to its attractive colors and peaceful nature. This fish is native to the Western Pacific Ocean, where it can be found in coral reefs and lagoons. In the wild, they feed on plankton and small crustaceans. 
Adult Blue Assessors usually grow up to 2 inches in length, making them ideal for smaller aquariums. They are hardy and easy to care for, which makes them a great choice for beginners. They do best in a well-established reef aquarium with plenty of hiding places and live rock for grazing.

In captivity, Blue Assessors should be fed a varied diet consisting of frozen or live foods such as brine shrimp, mysis shrimp, and chopped krill. They may also accept high-quality flake and pellet foods, but a varied diet is important to ensure they receive all the necessary nutrients.

It is difficult to determine the sex of Blue Assessors by external characteristics alone. However, males are known to be slightly larger and more colorful than females.

Breeding Blue Assessors in captivity is challenging but not impossible. They are known to be protogynous hermaphrodites, which means they start their lives as females and later transition into males. In the wild, spawning typically occurs during the spring and summer months. If breeding is desired, it is recommended to have a small group of Blue Assessors and provide them with a well-established aquarium with plenty of hiding places and live rock.

Blue Assessors are generally hardy and disease-resistant. However, they may be susceptible to common saltwater fish diseases such as ich, velvet, and bacterial infections. Maintaining good water quality and providing a varied diet can help prevent illness.

The Blue Assessor (Assessor macneilli) is native to the Western Pacific Ocean, specifically in the Philippines and Indonesia.

Blue Assessors are peaceful and do well in a community aquarium. However, they may become aggressive towards other similar-shaped species. It is best to keep only one male Blue Assessor per aquarium to prevent aggression.

When introducing Blue Assessors to a new aquarium, it is important to acclimate them slowly. The drip acclimation method is recommended, where the fish is slowly acclimated to the new water by adding small amounts of the new aquarium water to the bag over a period of several hours.