Ostraciidae is a family of squared boney fish belonging to the order Tetraodontiformes. , 

These fish are closely related to file fish and puffer fish. They have hexagonal scales that are interlocked making the surface of the body solid and hard like a defensive armor. If the hardened scales are not enough to deter a predator, the box fish has a water soluble toxin it can release when threatened or when it dies. This is fantastic defense against predators in the wild but makes them a difficult species to keep in an aquarium.  In captivity box fish usually reach sixteen inches or less, however in the wild they commonly exceed twenty inches long depending on species.

These fish are classified as "reef safe with caution." I would like to edit that a bit and call them "aquarium safe with caution," They have a chance of eating invertebrates and nipping at corals in a reef, but the toxin they can release is hazardous in whatever tank they might be in. Take care when adding one of these to an existing tank. If possible it is best for it to be one of the first fish added to the tank after it is cycled.

Be sure that you have the proper items to make a tank safe fro them seeing as how they could be the first fish in the tank. Aqua Life's Activate and Aqua Life Complete are both useful. They prefer a specific gravity of 1.020-1.025. You can get this with the AquaLife's one salt, mixed to the right proportions this is good salt for a reef or fish only. Make sure to check your specific gravity with a Reefractometer. The Reefractometers are much more acurate then the hydrometers that you can pick up here at Aquarium.