"Use caution if placing the Spotted Boxfish in a reef tank as they will  often nibble at tubeworms. If stressed, the Cubicus Boxfish releases a  poisonous substance, called ostracitoxin, from its mucous glands which  will kill other fish in the tank very quickly"
"Use caution if placing the Cowfish Longhorn in a reef tank as it may  nibble on tubeworms. When housed correctly, the Cowfish Longhorn is  long-lived. Similar to other boxfish, the Cowfish Longhorn's skin is poisonous and,  when threatened, it will release a toxin lethal to other tank members,  including other Longhorns."