Blue Assesor Basslet (Assesor Macnelli)

The Blue Assessor Basslet is a stunning, deep blue fish that makes a unique and colorful addition to marine aquariums. Known for its calm and peaceful demeanor, this basslet is a popular choice among aquarists, particularly for reef tanks. One of the most fascinating behaviors of the Blue Assessor is its distinctive swimming pattern—it often swims upside down, a trait developed from its natural habitat in caves and under rocky ledges.

Care Information

• Maximum Size: Up to 3 inches.
• Tank Size: 30 gallons minimum; larger tanks are preferred, with plenty of hiding spots and caves to mimic its natural environment.
• Diet: Carnivorous; feeds on small meaty foods like mysis shrimp, brine shrimp, and finely chopped seafood. It also accepts high-quality frozen and pellet foods.
• Water Temp: 74-78°F.
• Salinity: 1.020-1.025.
• Aggression: Peaceful; gets along well with other small, non-aggressive species and is best kept in community tanks with similar temperament fish.
• Skill Level: Beginner to Intermediate; hardy and relatively easy to care for, making it suitable for most aquarists.
• Reef Compatibility: Reef-safe; does not harm corals or invertebrates and thrives in a reef environment.

Unique Swimming Behavior
One of the most interesting traits of the Blue Assessor Basslet is its tendency to swim upside down. This behavior is a result of its natural cave-dwelling habitat, where it often swims along the ceilings of caves and under ledges. This fascinating upside-down swimming pattern adds character to any tank, making the Blue Assessor a delightful and unique species to observe.

Coloration

• Western Pacific: The Blue Assessor Basslet is typically a deep, vibrant blue color that stands out beautifully in a reef tank. Its coloration may vary slightly depending on environmental conditions and lighting​.

Typical Habitat

• Distribution: Native to the Western Pacific, the Blue Assessor Basslet is often found in caves and under ledges in coral reefs. It prefers environments with plenty of rockwork and overhangs, where it can display its unique swimming behavior while foraging for food​