Aquarium Livestock Pet Care Guides

Boxfish, Cowfish & Trunkfish


Indo-Pacific, coastal Atlantic

Tank Temperature




Specific Gravity



Omnivorous; brine shrimp, krill, other frozen meaty foods, tunicates, sponges; may ingest polychaete worms, algae, small bivalves, and gastropods; may nip at corals, fanworms, & clam mantles


Docile; peaceful; grazes on algae; will browse for invertebrates; aggressive towards other fish of the same species


Community Safe; Coral Safe with caution; not invert safe. Can be kept with docile tankmates. Use caution when housing with other boxfish, damsels, groupers, hawkfish, puffers, triggers, corals, and invertebrates.

Species Overview

Boxfish, Cowfish, and Trunkfish are in the Ostraciidae family. Ostraciidae, from the Greek "ostracum", means "shell", a fitting name because these fish have rigid, box-like or pyramid-shaped bodies. Their interesting shapes are enticing to many aquarists. They are often brightly colored and adorned with beautiful patterns, which adds to their appeal. Many aquarists consider them to be extremely friendly and full of personality.

This family is also known for the ability to produce "ostracitoxin", a toxic substance which may be released when they are stressed. Though this is rare, caution should be used when netting, acclimating, and choosing tankmates if you intend to keep one of these fish.

Many members of this family can grow very large, a larger tank set-up is necessary. They should be placed only in well-established tanks with plenty of open swimming space. Tankmates also need consideration. Keeping them with fast-moving, aggressive fish is not recommended. Overly active and nippy tankmates may stress Boxfish, Cowfish, and Trunkfish, and make it hard for them to feed adequately. The skin over their bony plates is quite sensitive and can easily be damaged by aggressive tankmates. Abrasions on the skin may increase the possibility of a bacterial or fungal disease.

Avoid keeping more than one of the same species of Boxfish, Cowfish, and Trunkfish in your tank. They are known to be territorial and aggressive towards others of their kind.

If properly cared for, they can live in an aquarium for years and provide you with a rewarding experience!

We always suggest that you do further research before adding a new pet to your tank. What we have provided for you are guidelines and suggestions. If you have any further questions or concerns, please contact our fish room at 717-299-5691 ext. 1213 or

Recommended Items

Protein Skimmer
Acclimation Kit
Sea Veggies