



BOXFISH – CUBICUS Ostracion cubicus
$139.99
The Cubicus Boxfish, also referred to as the Yellow Boxfish, Polka Dot Boxfish, or simply Cubicus, is native to the Indo-Pacific. Typically offered at smaller sizes, juvenile Cubicus are yellow with many brown to black spots. As they mature, this yellow color becomes duller. Sometimes confused with the Longhorn Cowfish (Lactoria cornuta), however the cowfish possesses a pair of “horns” that distinguishes it from the Cubicus boxfish. While these fish can grow to an impressive 15″ in the wild, they stay significantly smaller in the home aquarium. Boxfish are often admired for their “puppy-like” behavior, in which they may eventually associate the hobbyist as their caretaker and therefore, will beg for food at the front of the aquarium. Exercise caution to not overfeed; select a feeding schedule that works best for you, your boxfish and aquarium as a whole.
Care Level: Advanced
Temperament: Peaceful
Reef Compatible: With Caution
General Description: The Cubicus Boxfish, also referred to as the Yellow Boxfish, Polka Dot Boxfish, or simply Cubicus, is native to the Indo-Pacific. Typically offered at smaller sizes, juvenile Cubicus are yellow with many brown to black spots. As they mature, this yellow color becomes duller. Sometimes confused with the Longhorn Cowfish (Lactoria cornuta), however the cowfish possesses a pair of “horns” that distinguishes it from the Cubicus boxfish. While these fish can grow to an impressive 15″ in the wild, they stay significantly smaller in the home aquarium. Boxfish are often admired for their “puppy-like” behavior, in which they may eventually associate the hobbyist as their caretaker and therefore, will beg for food at the front of the aquarium. Exercise caution to not overfeed; select a feeding schedule that works best for you, your boxfish and aquarium as a whole.
Diet Requirements: In the wild Cubicus are omnivorous, feeding upon benthic algae, tubeworms, and various microorganisms. In the aquarium, Cubicus should be offered a variety of high quality frozen meaty foods, enriched shrimps, and foods containing algae such as Spirulina, Chlorella, and pieces of marine sheet algae for variety. It is not uncommon for Cubicus to ignore food upon introduction and that they can be extremely stubborn with accepting frozen foods at first. Offering live adult brine shrimp or black worms can help bridge the transition to frozen foods. We highly encourage soaking frozen foods in vitamin and fatty acid supplements for the boxfish’s health and to maintain body mass. Cubicus are slow eaters, and should not be housed with aggressive feeders that may out compete them in food resources. Note: Our Cubicus boxfish for sale are eating a combination of live foods and frozen foods, or frozen foods only. It is not uncommon for this species to revert back to only accepting live foods, or ignore food altogether, for a period of time due to the stress of a new environment.
Care Requirements: An established minimum 90 gallon aquarium is ideal to house a single Cubicus. While this size aquarium may seem like overkill for its size, it allows the Cubicus room to grow and to dissipate in greater volume any toxin that could be omitted by this fish. We highly suggest having carbon filtration on the aquarium as well to extract toxin from the water volume. Boxfish cannot tolerate nitrite or ammonia spikes and absolutely need generous live rock for feeding and some crevices to take refuge. Water movement should be on the gentle side because boxfish are not extremely powerful swimmers, and can easily be blown around. Cubicus may be housed together if all individuals are added at once. Do not house them with aggressive and extremely active tank-mates; a Cubicus would thrive best in a very timid and laid back fish only with live rock aquarium as they may nip certain sessile invertebrates in a reef aquarium. Recommended water conditions, 72-78° F, KH 8-12, pH 8.1-8.4, salinity 1.020-1.025
Purchase Size: Small: 2-1/4″ or less; Medium: 2-1/2″ to 3-1/4″
Note: Your item may not look identical to the image provided due to variation within species. Purchase sizes are approximate.
Caution:Â This species secretes or releases toxins when stressed or injured that may kill fish in the aquarium. Aquatics Unlimited cannot accept responsibility for any loss that may occur should this animal poison the aquarium.
Dry goods orders are shipped via US Postal Service or UPS to the address provided at checkout based on the selection made in your website shopping cart. Product is carefully packed to help prevent any damage during shipping. Once processed you will receive a shipment notification via email with tracking number, and delivery notification. Please allow 48 hours for processing after your order is placed.
Perishable items (i.e. live plants, refrigerated/frozen foods) are shipped via US Postal Service 2-3 day to the address provided at checkout for a $25.00 flat rate charge. Items are packed with secure packing material and heat, cold, or Cryo packs as needed to maintain safe temperatures during transit. If one or more perishable items are in the shopping cart at checkout the $25.00 perishable shipping charge will automatically appear and need to be selected. Once processed you will receive a shipment notification via email with tracking number. Please allow 48 hours for processing after your order is placed.
Livestock (i.e. fish, invertebrates, coral) are shipped via UPS Overnight to the address provided at checkout for a $55.00 flat rate charge. Livestock is packed in insulated styrofoam boxes with secure packing material and heat, cold, or Cryo packs as needed to maintain safe temperatures during transit. If one or more livestock items are in the shopping cart at checkout the $55.00 livestock shipping charge will automatically appear and need to be selected. Livestock is shipped Monday through Wednesday ONLY (no weekend delivery is available) weather permitting, and we reserve the right to delay shipping until conditions are appropriate for safe arrival. Once your order is placed we will contact you to arrange the best shipping date based on these criteria. Someone must be available to receive the livestock order on the first delivery attempt. Once processed you will receive a shipment notification via email with tracking number. Please allow 48 hours for processing after your order is placed.
For mixed dry goods/perishable & livestock orders items will be shipped via their corresponding shipping methods outlined above. Dry goods will be shipped via US Postal Service or UPS based on your selection and checkout, while livestock will ship via UPS Overnight for a $55.00 flat rate charge. You will receive separate notifications and tracking numbers for the dry goods and livestock. Please note due to different carriers and shipping methods dry goods and livestock may arrive on different days.
Related products


BUTTERFLY – COPPERBAND Chelmon rostratus
$109.99 – $219.99

BUTTERFLY – HENIOCHUS BLACK & WHITE Heniochus acuminata
$119.99 – $249.99

ANGEL DWARF – PYGMY ATLANTIC / CHERUB Centropyge argi
$69.99 – $99.99

WRASSE – LEOPARD VERMICULATE Macropharyngodon bipartitus
$129.99TANG – SAILFIN DESJARDINII Zebrasoma desjardinii
$169.99 – $199.99

TANG – LIEUTENANT Acanthurus tennenti
$139.99 – $209.99

RABBITFISH – TWO BARRED Siganus virgatus
$89.99 – $199.99
