Overview
The Square Block Anthias, also known as the Squarespot Anthias, is a larger and more robust anthias species than many others in the trade, with males displaying a bold pink body and a distinctive dark square-shaped patch on the flank. It's a striking centrepiece anthias for a larger reef display.
Like other anthias it's naturally social and does best kept in a small group with one male and several females, showing more natural colour and behaviour in this arrangement than as a lone individual.
Its larger adult size compared to many anthias means it needs a bit more room, but it also tends to be somewhat hardier and more adaptable than some of the smaller, more delicate anthias species.
Compatibility
Square Block Anthias are peaceful and reef safe, ignoring corals and invertebrates entirely. They do best in a group of one male with several females, and generally coexist well with other peaceful reef fish, though boisterous or fast-feeding tankmates can outcompete them for food.
Multiple males in a small tank may show aggression toward each other, so stocking ratios matter if keeping a group.
Health & quarantine
As with all anthias, this species can decline quickly if underfed or exposed to unstable water conditions, so a mature tank and consistent feeding schedule are essential. A minimum two-to-four-week quarantine with careful feeding monitoring is recommended, and new arrivals should be watched closely to confirm they're eating well.
Frequently asked questions
Should I keep Square Block Anthias alone or in groups?
How big does a Square Block Anthias get?
Is the Square Block Anthias reef safe?
How often do Square Block Anthias need to be fed?
What tank size suits a group of Square Block Anthias?
Care guidance is drawn from our own experience — every fish is an individual, so treat it as a starting point, not a guarantee. Not sure if a species suits your tank? Come ask us in store. New to the terms? Read the care-terms glossary.