Boxfish
Smooth Trunkfish
Boxfishes at a Glance
👁️ How common: Common
🔬 Scientific family: Ostraciidae
📏 Size: Approximately 10–50 cm (4–20 in), depending on the species
🌊 Habitat: Coral reefs, rocky areas, seagrass beds and sandy bottoms
⬇️ Depth: Mostly shallow coastal waters and reefs, although some species occur much deeper
🌿 Diet: Algae, sponges, tunicates, molluscs, crustaceans and other small invertebrates
🌎 Distribution: Tropical and subtropical waters of the Atlantic, Indian and Pacific Oceans
🐠 Behaviour: Generally solitary, slow-moving and peaceful
🥚 Reproduction: Eggs and sperm are released into the water column
🛡️ Special feature: The body is enclosed in a rigid armour of fused bony plates, leaving only the fins, mouth and tail free to move
☠️ Defence: Some species can release a toxic substance from their skin when severely stressed or threatened
🎨 Colour: Patterns range from spots and honeycomb markings to bright blues, yellows and browns
🐣 Juveniles: Often more brightly coloured and differently patterned than adults
♻️ Ecological role: Feed on algae and a variety of small reef organisms and form part of the diverse reef food web
🏝️ Curaçao, Bonaire & Aruba: Species include the Smooth Trunkfish, Spotted Trunkfish, Honeycomb Cowfish and Scrawled Cowfish.
What makes them special?
Boxfishes are among the most unusual-looking fish on Caribbean reefs
Their bodies are enclosed in a rigid shell-like structure made of bony plates, giving them their characteristic box-shaped appearance. Despite their rather awkward shape, they are surprisingly agile and manoeuvrable around the reef.The hard body armour provides excellent protection from predators. Unlike most reef fish, boxfishes cannot simply bend their bodies from side to side. Instead, they swim using their fins, making small, precise movements that allow them to hover and manoeuvre between corals and rocks.
Toxic
One of the most fascinating things about boxfishes is their defence mechanism. When seriously threatened, some species can release toxic substances into the surrounding water. These toxins can be harmful or even deadly to other fish. It is an unusual and highly effective form of chemical defence.
Baby boxfish are super cute!
Young boxfishes often have much brighter colours and more dramatic patterns than adults. Some juveniles are covered with spots, stripes or bright yellow colouring that gradually changes as they mature.
This makes them particularly interesting to identify underwater, the little fish you see may look surprisingly different from the adult of the same species.