Square Anthias

Care at a glance

Overview

Timid and easily stressed when new, slower to start feeding than other anthias, and best added to a tank with existing anthias or other peaceful fish already settled in. It needs several feedings of small meaty foods a day and does poorly on one or two large meals. Males fight other males of the species to the death, so keep only one per tank, ideally with four to six females; females also peck at smaller conspecifics, so add similarly sized individuals together. It is fully reef safe with corals and invertebrates but should be kept away from aggressive tankmates, large angelfish, and predatory fish that could bully or eat it.

In the wild

Ranges across the western Pacific and into the eastern Indian Ocean on outer reef slopes and drop-offs, from the shallows down past 100 m though most common in the top 25 m. It needs a large aquarium with a long, open swimming lane above a substantial rock structure, since males patrol and defend a real territory. Keep lighting on the lower, indirect side, since harsh light washes out its color and adds stress.

Good to know

A protogynous hermaphrodite and harem former: females hold their own pecking order within a group, and the largest female steps up to replace a lost male. It shows strong sexual dimorphism: females are yellow-orange with a lavender belly, while males turn a deep pink to reddish-purple with a squared-off patch of color on the flank that gives the species its common name. It is one of the largest anthias kept in the hobby.

Did you know

The dominant male's square block of purple-pink color is a signal of status that subordinate males and females never show, so the presence of a fully colored square patch is a reliable sign of which fish is running the harem.

Related species

• 

  Bicolor Anthias

  Pseudanthias bicolor

  5.1 in (13 cm)125 gal (475 L)72–79°F (22–26°C)

• 

  Lyretail Anthias

  Pseudanthias squamipinnis

  5.1 in (13 cm)79 gal (300 L)75–81°F (24–27°C)

• 

  Huchtii Anthias

  Pseudanthias huchtii

  4.7 in (12 cm)90 gal (340 L)75–81°F (24–27°C)

• 

  Evansi Anthias

  Pseudanthias evansi

  4.7 in (12 cm)75 gal (285 L)75–81°F (24–27°C)

• 

  Purple Queen Anthias

  Pseudanthias tuka

  4.7 in (12 cm)75 gal (285 L)75–81°F (24–27°C)

• 

  Dispar Anthias

  Pseudanthias dispar

  3.7 in (9.5 cm)70 gal (265 L)72–79°F (22–26°C)