Squareblock Anthias

Many of the anthias are brightly pigmented, but few can match the color of an adult male Pseudanthias pleurotaenia. This tropical fish, known as the squareblock anthias, will glow like a neon sign if provided with a proper diet and kept in the right conditions. The squareblock anthias larger size makes it an even more stunning addition to the home aquarium.

Difficulty: While all the anthias can be a bit challenging to keep long-term, the squareblock anthias is one of the easier species to maintain. The key is food. You have to add meaty foods (finely shaved seafood, frozen Cyclops, fish eggs and carnivore foods) at least three times a day. If you do not feed the active squareblock anthias enough food, it will become more and more emaciated and will gradually perish.

Physical Description: The male squareblock anthias has orange and magenta colors with a brilliant pink square on each flank. This marking serves to signal females and rival males in its natural habitat. At the depths the squareblock anthias is usually found, the square glows, making the male Pseudanthias pleurotaenia even more conspicuous. The female squareblock anthias are yellow, and their scales are edged in orange and violet-edged yellow lines that run from the eye to the origin of the tail. The squareblock anthias is very similar to Shen’s anthias (Pseudanthias sheni), which is rarely seen in the trade due its very limited distribution (it is only known from Rowely Shoals, Northwestern Australia). The squareblock anthias reaches a size of about 8 inches.

Range: The squareblock anthias is found from Samoa to Indonesia, where it typically resides on fore reef slopes and reef drop-offs. Pseudanthias pleurotaenia is particularly abundant in areas subjected to stiff current, which serves to transport life-giving food (zooplankton). The anthias swims above the reef and snags the tiny prey items out of the water column. The squareblock anthias tends to prefer moderate depths — usually deeper than 90 feet. The squareblock anthias is usually found in smaller, looser shoals than some of its kin.

Compatibility: Most people are drawn to keeping anthias after they see a shoal of them hanging over the reef. You may have had the good fortune of seeing these tropical fish in the wild or you may have seen it on a television show. Either way, it is an awe-inspiring sight! The only problem is that this scene can be difficult to replicate in the average home aquarium. To keep a shoal of squareblock anthias, you will need plenty of space (i.e. a big aquarium, preferably 180 gallons or more) and you will need to add one male and a handful of females (e.g., three to five). Male Pseudanthias pleurotaenia are dominant and aggressive toward females to discourage them from changing sex. Female squareblock anthias also maintain a hierarchy – typically the bossiest female will change sex if the male is removed. In a smaller aquarium, this can lead to more subordinate fish being harried to death by their dominant shoalmates. While the squareblock anthias may behave aggressively toward conspecifics or even its close relatives (other anthias), the squareblock anthias is likely to pay little mind to non-related aquariummates. It may occasionally chase other zooplanktivores (e.g., flasher and fairy wrasses, dartfish) but rarely cause them any harm.

Aquarium Conditions: Many of the anthias that live at greater depths lose their bright colors with time in captivity. It has been suggested that this occurs because of dietary deficiencies. There is no doubt that a lack of certain pigments in the anthias diet may contribute to color loss, but it also may be a function of being kept under unnaturally bright lighting. The intense lighting often found over reef aquariums, for example, may actually cause anthias fish to fade. The best way to maintain color intensity is to keep anthias in a moderately lit aquarium (e.g., a deepwater reef aquarium) and to feed a varied diet high in color-enhancing pigments. An aquarium of 55-gallons is sufficient for a solitary squareblock anthias, but a much larger aquarium will be required to keep a shoal of this fish. Keep the squareblock anthias at a pH of 8.1 to 8.4, specific gravity of 1.019 to 1.025 and a water temperature of 76 to 82 degrees Fahrenheit.

Care Considerations: Strong water flow and good protein skimming will help keep your Pseudanthias pleurotaeniain top condition. An aquarium cover of some sort will also prevent the squareblock anthias from leaping to its death.

Breeding: The squareblock anthias is not likely to spawn in your home aquarium. The squareblock anthias is a protogynous hermaphrodite, meaning males result from female sex change.

Breed Details

Country of Origin:
Samoa to Indonesia, on fore reef slopes and reef drop-offs