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Interesting Facts about the Shortnose Boxfish
[Phylum: Chordata] [Class: Actinopterygii] [Order: Tetraodontiformes] [Species: Ostracion nasus]
Most of the 23 extant boxfishes are resident in the Indo-Pacific biogeographic region. Yet, compared to the others, one of them has a much shorter snout.
This guide contains some surprising facts about the spotted shortnose boxfish, such as where they live, what they like to eat, and how these cube-shaped fish reproduce.
Ostracion nasus Habitats and Distribution
The boxfish classification Actinopterygii inhabits most of the tropical and subtropical marine environments.
Yet, shortnose boxfishes tend to thrive better in several key regions, more specifically:
- Australia (especially in northern Australia dive sites)
- Central Pacific Regions (e.g. Micronesia, Fiji, Melanesia)
- Southeast Asia (e.g. Indonesia dive sites, Thailand dive sites)
- The Red Sea (including some dive sites in East Africa)
The spotted shortnose boxfish lives around shallow coral reef formations that provide a mix of soft substrates and sheltered hiding places, such as algae beds.
Despite preferring the safety associated with shallow reef flats, these cuboid aquatic vertebrates are also found at depths approaching 50 metres (165 feet).
Fun Fact: The boxy shape of the body is far from "hydrodynamic". But, these marine vertebrates are quite agile and can swim or hover using their tiny fins in a kind of "rowing" maneuver.
Shortnose Boxfish Characteristics
The angular shape of their white or grey rigid bony carapace with reticulated dark spots, and a shorter nose, are the primary features that distinguish them from the other species of boxfishes.
In fact, the bony structure contains fused armoured scales that encase most of the body parts. It provides some protection against their natural predators in the wild, especially groupers, moray eels, octopuses, snappers, and carnivorous sharks.
Here's the thing:
The average size for a fully matured spotted shortnose boxfish is about thirty (30) centimetres long (12 inches).
Like most aposematic marine animals, Rhynchostracion nasus is mostly a solitary species that also tries to mimic poisonous marine creatures to help them avoid capture, such as toxic nudibranch species.
Are Boxfish Poisonous to Humans?
The secretion of a toxic slime (ostracitoxin) by some boxfishes, including the yellow boxfish (Ostracion cubicus), is used to evade capture by potential predators when they feel stressed or threatened.
Hence, this defencive action is likely to impact other common home aquarium fish when kept in the same tank as a cubed boxfish.
What Do Short Nosed Boxfish Eat?
Being a typical omnivore means the boxfish species (Ostraciidae) are comfortable eating a healthy combination of animal and plant matter, including:
- Benthic epifauna (e.g. barnacles, echinoderms)
Copepods- Detritus
- Fish fry
- Green algae
- Krill
- Marine mollusks
- Sponges
- Tiny crustaceans
- Tunicate sea squirts
- Worms (annelids)
Pro Tip: Some of the best places to see shortnose boxfishes are the scuba diving spots in Bali and some of the Phuket dive sites.
Shortnose Boxfish Reproduction
The average lifespan for most boxfish types is about four (4) years. However, compared with many other marine vertebrates, they have a slow reproductive rate.
They start broadcast spawning when the warm water arrives - usually towards the end of spring. After forming a group, usually one (1) male and up to four (4) females, they begin the mating ritual (dancing in small circles) near shallow reef structures.
Key takeaways:
Accurate information about the breeding habits of the boxfish species is generally limited. Even so, biologists have determined that females lay lots of eggs on a daily basis for about one month.
Following that, the male boxfish will release his sperm to fertilise the eggs as they float in the water column near the surface.
After the tiny larvae hatch, usually within 48 hours, they drift in the open ocean and feed on plankton until they grow big enough to settle on a reef as juveniles.
Threats and Predators
The IUCN Red List of Threatened Species assessed the yellow boxfish (Ostracion cubicus) in 2023 and specified them as being of "Least Concern" (LC).
However, some of the contributing factors for a decline in certain vulnerable areas include certain types of human behaviour (e.g. coral reef destruction and degradation, overfishing, the aquarium trade, and warming seas).