Half Black Mimic Tang

Half Black Mimic Tang: The Rare Reef Herbivore

The Half Black Mimic Tang (Acanthurus chronixis), also known as the Chronixis Surgeonfish, is a rare species within the group of tangs famous for mimicking dwarf angelfish as juveniles. Its natural distribution is highly restricted, making it uncommon in the aquarium trade.

As a juvenile, this fish closely mimics the coloration of the Half Black Angelfish (Centropyge vrolikii) as a defense mechanism against predators. Adults typically reach a size of 8-10 inches (20-25 cm) and mature into a darker coloration, often displaying a mix of tan, brown, and black. A minimum aquarium size of 120 gallons is necessary to provide ample swimming room, as this species is constantly grazing.

The Half Black Mimic Tang is considered a peaceful to semi-aggressive addition to the marine aquarium, generally focusing its aggression on other tangs, particularly those of similar size or shape.

Diet & Compatibility:

• Diet: This fish is a primary Herbivore (algae-eater). Its diet must consist mainly of marine-based vegetable matter, including dried seaweed (nori) offered multiple times per week using a veggie clip. This is crucial for its health and immune system. Supplement the diet with high-quality herbivore pellets and flakes, along with occasional meaty foods like mysis shrimp.
• Algae Control: Like all tangs, the Half Black Mimic Tang is an excellent natural algae grazer and will spend its days picking filamentous and microalgae from live rock and glass.
• Reef Compatibility: It is generally considered Reef Safe. It will not bother corals or most ornamental invertebrates, focusing its grazing efforts on nuisance algae.
• Temperament: It is Peaceful toward most non-tang fish, but can be territorial or semi-aggressive toward other tangs and surgeonfish. It should be the only fish of its species unless introduced as a mated pair in a very large system. Provide plenty of live rock and caves to establish territories and break up sight lines.

Quick Facts

• Scientific Name: Acanthurus chronixis
• Primary Common Name: Half Black Mimic Tang
• Other Common Names: Chronixis Surgeonfish
• Origin: Western Pacific (Primarily Kapingamarangi Atoll, Caroline Islands)
• Max Size: 8-10 inches (20-25 cm)
• Temperament: Semi-Aggressive (Targeting other tangs)
• Diet: Herbivore (Must include marine algae/nori)
• Minimum Tank Size: 120+ Gallons
• Reef Compatibility: Yes