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Cubicus Boxfish

Ostracion cubicus


(1 Reviews)

Cubicus Boxfish
The Cubicus Boxfish is a captivating addition with its unique box-shaped body and bright yellow hue. It's relatively easy to care for and thrives in large stable saltwater setups, bringing a distinctive look and personality to any aquarium.

Expert Only

Cubicus Boxfish

Ostracion cubicus


(1 Reviews)

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Cubicus Boxfish Care Facts

Care Level: Expert
Temperament: Semi-Aggressive
Diet: Omnivore
Reef Safe: No
Minimum Tank Size: 120 gallons
Max Size: 18 inches
The Yellow Cubicus, Ostracion cubicus, also known as the Cubicus Boxfish, Yellow Boxfish, Polka Dot Boxfish, or Cube Boxfish, This fish is one of the most unique marine fish species available. At the juvenile stage, they are easily identifiable as they have a yellow box-shaped body with brown spots. But in the  adult stage, the yellow will fade and become brown.  Their incredibly unique box-shaped body makes them a fun and entertaining fish to watch in your tank. However, the Yellow Cubicus is fickle and should only be cared for by expert and  experienced aquarists. They can reach a size of 15 inches, and should be kept in a tank no less than 100 gallons, with plenty of live rock and a sand substrate. It is a great reef fish as long as it is not kept with larger, more aggressive or speedy fish. Be sure not to house the Yellow Cubicus with cleaner type fish as well,  as it has sensitive skin, and they do secrete poison from skin glands when stressed or in danger. This poison may kill fish in the aquarium very quickly.  Also be sure to keep the lid on your tank tightly sealed to prevent jumping. The Yellow Cubicus can pick on smaller inverts and tubeworms once it gets larger so plan accordingly. The Yellow Cubicus should be fed an omnivore diet. When first introduced to the tank, the Yellow Cubicus prefers a diet of live Brine shrimp or Mysis. And when acclimated, their diet should include chopped Squid, Clams, Mussels, and herbivore preparations for variety. They will thrive in a temperature range of  72-78?? F and a pH of 8.1-8.4.

Unveiling the World of the Cubicus Boxfish: A Guide for Marine Enthusiasts

The Cubicus Boxfish (Ostracion cubicus) emerges as a captivating and unique treasure within your saltwater marine aquarium. Native to the warm and vibrant waters of the Atlantic, ranging from the eastern coast of the Americas to the west coast of Africa, this species thrives amidst the intricate ecosystems of coral reefs and rocky outcrops.

The Cubicus Boxfish's Ideal Habitat and Compatibility with Reefs

In their natural habitat, Cubicus Boxfish are often found navigating through tropical reefs' crevices and coral formations. Their compatibility with reef environments raises pertinent considerations. While their charming appearance and geometric structure are captivating, they possess specific characteristics that might impact reef ecosystems. They have been known to feed on small invertebrates and algae, potentially affecting the delicate balance of coral and invertebrate growth. They are not reef safe.

Size and Lifespan of the Cubicus Boxfish

With its distinctive box-like appearance and striking coloration, the Cubicus Boxfish grows to an average length of 6 to 8 inches in captivity and 18 inches in the wild. When provided with optimal care and a suitable environment, this species has the potential to live for approximately 5 to 10 years, offering enthusiasts a captivating and enduring marine companion.

Diet in Captivity: What the Cubicus Boxfish Needs to Thrive

Recreating the Cubicus Boxfish's natural diet in captivity is crucial for its well-being. A diet that reflects its herbivorous tendencies includes high-quality marine-based pellets, various frozen foods, and offerings of live or frozen algae and seaweed. Fulfilling their nutritional needs supports their vitality and helps maintain their vibrant appearance.

Aquaculture and Availability: Balancing Ethical Practices

Significant aquaculture efforts for the Cubicus Boxfish are limited, and most specimens available to hobbyists are wild-caught. As the field of aquaculture continues to evolve, responsible sourcing and ethical collection practices are paramount in ensuring the health and well-being of the species during their transition to captivity.

How Compatible is the Cubicus Boxfish with Other Fish and Invertebrates

The temperament of the Cubicus Boxfish leans towards a peaceful disposition, but caution is still advised when selecting tank mates. Suitable companions often include fish species with similar demeanor and size, such as the Bicolor Blenny (Ecsenius bicolor) and the Royal Gramma (Gramma loreto). However, due to its potential territorial nature, monitoring interactions closely is advisable.

Temperament and Tank Requirements for the Cubicus Boxfish

  • The Cubicus Boxfish is characterized by its docile and gentle temperament.
  • A tank with a minimum capacity of 120 gallons is recommended to provide an accommodating habitat.
  • Water conditions should closely mimic their natural habitat, with a pH level ranging from 8.1 to 8.4, a salinity between 1.020 and 1.025, and a 72 to 78 degrees Fahrenheit temperature.

Compatible Tank Mates With the Cubicus Boxfish

Alternative Common Names for the Cubicus Boxfish

The Cubicus Boxfish may also be recognized by its alternate common names, including the Yellow Boxfish and the Polka-dot Boxfish.

Choosing the Cubicus Boxfish from Saltwaterfish.com

Opting to acquire the Cubicus Boxfish from Saltwaterfish.com offers enthusiasts a distinctive opportunity to introduce a captivating and unique marine inhabitant into their aquarium. As a trusted source for marine life, Saltwaterfish.com strongly emphasizes the health and well-being of the species it offers. Through rigorous collection, shipping, and acclimatization procedures, the Cubicus Boxfish arrives in prime condition, ensuring its seamless integration into your marine ecosystem.

In conclusion, with its captivating appearance and unique characteristics, the Cubicus Boxfish can be a fascinating addition to your saltwater marine aquarium. By understanding its specific care requirements and creating an environment that mirrors its natural habitat, you can provide a comfortable and enriching home for this intriguing species.


Expert Only: Items designated as expert only require special care such as a species specific environment, special diet or care, and an expert level, experienced aquarist. Not for beginners. Expert Only items qualify for our live arrival guarantee only, and are exempt from our extended 8 day guarantee.

The Cubicus Boxfish was received in great shape and has added life to my saltwater aquarium. Thanks


Reviewed by: Noel Henricks on Sept. 12, 2021

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