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What is a Boxfish?

Anna T.
Anna T.

Boxfish are a type of fish belonging to the Ostraciidae family of fishes. They are box-shaped and usually on the small side, not often exceeding five inches (12 cm) in length. A layer of bony plates on the scales helps to protect them against attacks by larger predators. Females are typically brown with white spots, and males are brown with blue, gold, and white spots. This type of fish is native to the Indo-Pacific ocean and can often be found near coral reefs, sand beds, and grass beds.

The average boxfish is non-aggressive by nature but may release a highly toxic poison when attacked or threatened. Sometimes it will also release it just after dying. This poison is capable of killing other aquatic life, including the fish that emits it. When the poison is released in nature, the boxfish normally swims away afterward to protect itself. Aquarium dwellers do not have this choice and often die as a result of spraying their own toxin.

Boxfish often eat crabs.
Boxfish often eat crabs.

Many people like to keep these fish in aquariums because of their bright colors and unique overall appearance. Other non-aggressive fish are generally the best options for aquarium mates. Putting them together with fish prone to fighting will likely result in the poison being sprayed. It is also not normally a good idea to place two male or two female boxfish together in the same aquarium because they may try to attack each other. If this occurs, and neither fish dies, chances are good that they will coexist peacefully afterward.

Boxfish are omnivorous, meaning they will eat both plants and meat. Some of the more common items they eat include crabs, shrimp, clams, seaweed, and coral. Boxfish are often slow eaters and may seem like they never have much of an appetite. It is usually not a good idea to feed them anything that floats on the surface of the water because they tend to become very disoriented after accidentally gulping air.

Other closely related fish also in the family Ostraciidae are cowfish and trunkfish. The cowfish is yellow with blue spots and horns on its head and a lower fin for defense. Trunkfish are generally very similar to the boxfish in appearance, but they often become much larger. Some trunkfish grow to a length of 12 inches (30 cm). Most fish in this family are alike in regard to temperament, habitat, diet, and defense with some slight differences in appearance.

Frequently Asked Questions

What exactly is a boxfish?

A boxfish is a member of the family Ostraciidae, a group of fish known for their distinctive box-like shape. Their bodies are encased in a hard, bony carapace made of fused scales, which provides protection from predators. Boxfish are found in tropical and subtropical seas, often around coral reefs where they feed on algae, mollusks, and small crustaceans.

How does the boxfish's shape benefit its survival?

The unique box-like shape of the boxfish provides several survival advantages. It makes them more difficult for predators to swallow and offers a sturdy armor against attacks. Additionally, the rigid body reduces flexibility but aids in stability and maneuverability among the complex structures of coral reefs, allowing them to navigate tight spaces with ease.

Are boxfish poisonous?

Yes, some species of boxfish are indeed poisonous. They possess a defense mechanism known as ostracitoxin, a potent toxin released from glands when the fish is stressed or injured. This toxin can be lethal to other fish in the vicinity and is a deterrent against predation. However, it is rarely harmful to humans unless ingested.

What is the diet of a boxfish?

Boxfish primarily feed on algae, benthic invertebrates, sponges, and small crustaceans. Their diet can vary based on their habitat and the availability of food sources. They use their small, protruding mouths to pick food off of surfaces and may also consume small fishes if the opportunity arises.

How do boxfish reproduce?

Boxfish reproduction involves external fertilization. The female releases eggs into the water column, which are then fertilized by the male's sperm. This process is often synchronized with lunar cycles or seasonal changes. The eggs are left to develop on their own, and once hatched, the larvae are planktonic before eventually settling to the reef.

Can boxfish be kept in home aquariums?

While boxfish are captivating creatures, they are not recommended for novice aquarists due to their specialized care requirements. They need large, stable, and well-maintained aquariums that mimic their natural reef environment. Additionally, their potential to release toxins when stressed makes them a risky choice for community tanks. Experienced hobbyists should only keep them with careful consideration and planning.

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    • Boxfish often eat crabs.
      By: tdoes
      Boxfish often eat crabs.