Description
Squareback Anthias – Pseudanthias pleurotaenia
Pseudanthias pleurotaenia, commonly called the Squareback Anthias or Squarespot Anthias, is a vibrant reef fish recognized for the distinct magenta “square” marking on the male’s flank. Females exhibit softer orange and pink tones, forming graceful shoals in the wild. This species is best suited to mature reef aquariums with stable conditions, open swimming space, and gentle water movement that mimics its natural midwater habitat.
Origin: Indo-Pacific region – from the Maldives and Indonesia to the Solomon Islands
Lighting: Moderate (enhances natural coloration without overstimulation)
Flow: Moderate to strong, consistent with reef slopes
Tank Placement: Midwater; appreciates open areas with rock structures for refuge
Temperature: 74–80°F (23–27°C)
Salinity: 1.022–1.026 SG
pH: 8.1–8.4
Diet: Carnivorous planktivore – thrives on small meaty foods such as mysis shrimp, enriched brine shrimp, and microplankton substitutes offered multiple times daily
Temperament: Peaceful; can form harems with one male and several females in large aquariums
Size: Up to 15 cm (6 inches)
Care Level: Advanced – requires frequent feeding and stable water parameters
Compatibility: Best for large, established reef systems with calm tankmates; avoid aggressive or boisterous species
