🐠 Blue Assessor (Assessor macneilli)
A Deep Navy-Indigo Body With Electric-Blue Fin Edging • A Natural Upside-Down Swimmer • A Hardy, Reef-Safe Nano Favourite
 
📋 The Blue Assessor, also known as Macneill's Assessor or Macneill's Basslet, has a rich, deep navy-indigo body with a thin electric-blue edge along the dorsal, anal, and pelvic fins.
It comes from the Western Pacific, from Australia's Great Barrier Reef to New Caledonia, where it lives in reef caves and crevices at shallow depths, often forming natural shoals of up to 100 fish. It has a charming, characterful habit: it swims and hangs upside down against cave ceilings and rock overhangs, a behaviour it carries straight into aquarium life. Every Blue Assessor we ship is feeding well.
It's fully reef safe, peaceful, and a natural planktivore that feeds on tiny crustaceans such as copepods and amphipods. It's territorial toward its own kind unless introduced together, so keep a single fish, or a group added at the same time to a tank of 280L or more. It's a capable jumper, so use a secure, hooded lid. It reaches about 6cm.
 
💡 Highlights
🎨 Deep Navy With Electric-Blue Fin Edging: A striking, popular nano basslet
🙃 A Natural Upside-Down Swimmer: Hangs against cave ceilings, just as in the wild
🌿 Fully Reef Safe: Won't harm corals or larger invertebrates
👥 Shoals in the Wild: Groups of up to 100 on the reef
🔒 Secure Lid: A capable jumper when startled