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Interesting Facts about Boxfishes
[Boxfish Phylum: Chordata] [Class: Actinopterygii] [Order: Tetraodontiformes] [Family: Ostraciidae]
They are consumed by humans and kept as exotic pets by some aquarists. In spite of that, or because of it, the 23 surviving species of boxfishes rank among some of the cutest fish on the planet.
Check out these endearing facts about boxfish (family Ostraciontidae) as we explain where they live, what kind of food they eat, and how these boxy cube-shaped fish get close enough to reproduce.
Boxfish Habitats and Geographical Range
The boxfish classification Actinopterygii is a saltwater fish that inhabits most tropical and subtropical oceans around the world.
Put another way, they are abundant in several key regions, especially:
- Australia (western and eastern coastlines)
- Indian Ocean (e.g. Indonesia dive sites, Thailand dive sites)
- Southeastern coast of the United States (including Gulf of Mexico)
- The Pacific Ocean (e.g. the Philippines, Fiji, Hawaii)
- Southeastern Atlantic Ocean (e.g. south coast of South Africa)
In general, boxfishes prefer to live around coral reef structures and sandy lagoons. Depending on the species, the depth range for these cuboid creatures varies between a few metres and down to depths approaching 250 metres (900 feet).
Fun Fact: The boxy appearance is not an obvious hydrodynamic design for cute marine vertebrates. Even so, their agility for swimming and hovering comes from a clever and distinctive combination of pectoral, dorsal, and anal fin "rowing" maneuvers.
Boxfish Characteristics and Behaviour
The unique "triangular" shape of the box-like bony carapace in boxfishes is the primary feature used to identify the species.
Yet, even though they're closely related to filefishes and pufferfishes, the bony structure that encases most of their body contains fused armoured scales that help to provide some protection against their natural predators (e.g. big fishes and sharks).
The body colouration for these scaly hexagonal plate-like skin patterns tends to be brown, blue, yellow, white, or black - sometimes with spots and lines.
However, it's more common for juvenile boxfishes to display brighter colours than the adults.
In fact, the ability to mimic toxic nudibranch species is often used as a defence mechanism to avoid capture.
Boxfish Size and Weight
Depending on the actual species, the average sizes for fully matured boxfishes range between seven (7) and forty (40) centimetres (16 inches) and they generally weigh less than 200 grams.
Pro Tip: One of the biggest boxfish species is the scrawled cowfish (Acanthostracion quadricornis) which can grow up to fifty (50) centimetres long (20 inches). By comparison, the shortnose boxfish (Ostracion nasus) is one of the smallest and reaches a maximum length of thirty (30) centimetres.
Boxfish Toxin
The secretion of a toxic substance (called ostracitoxin) by some species of boxfishes, especially the yellow boxfish (Ostracion cubicus), is used to evade capture by their predators if 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 boxfish.
What Do Boxfish Eat?
Being a typical omnivore means the boxfish species (Ostraciidae) are comfortable eating a healthy combination of plant and animal matter.
Thus, you may see them hovering over a sandy ocean floor searching for small crustaceans, worms, sponges, and krill. They will also consume any green algae that grows on rocky slopes.
Boxfish Species List
Buffalo Trunkfish (Lactophrys trigonus)
Horn-nosed Boxfish (Ostracion rhinorhynchos)
Longhorn Cowfish (Lactoria cornuta)
Roundbelly Cowfish (Lactoria diaphana)
Scrawled Cowfish (Acanthostracion quadricornis)
Shortnose Boxfish (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 and how these cube-shaped fish reproduce.
Smooth Trunkfish (Lactophrys triqueter)
Spotted Boxfish (Ostracion meleagris)
Triangular Boxfish (Tetrosomus concatenatus)
Yellow Boxfish (Ostracion cubicus)
There are many colourful boxfishes living in the wild and in captivity. Yet, the one with a bright yellow box shaped body and black spots stands out from the rest.
Another page contains some lesser-known facts about yellow boxfish (Ostracion cubicus), including where they thrive best, what kind of food they eat, and how these box-shaped fish reproduce.
How Do Boxfish Reproduce?
On average, the lifespan for most types of boxfish is about four (4) years. In addition, compared with many other marine vertebrates, they have a slow reproductive rate.
They tend to start reproducing when the warm water arrives in late spring. After forming a group, usually one (1) male and up to four (4) females, they begin the mating ritual.
Here's the thing:
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.
Threats and Predators
According to the endangered species red list, the current conservation status of most boxfish species is of "Least Concern" (LC).
Even so, some of the major contributing factors for the decline in certain vulnerable areas include certain types of human behaviour (e.g. coral reef destruction and degradation, overfishing).