Boxfish

Boxfish, in the family Ostraciidae, are found in the Atlantic, Indian and Pacific oceans. They achieve a length of 3 to 18 inches and exhibit a variety of colors. They also feature hexagonal or "honeycomb" platelike scales. Boxfish may pose a hazard in a community tank. When threatened or dying, they can release a toxin that can kill other fish, as well as themselves.