Yellow Boxfish

The Biological Weapon (Ostracitoxin Poison):

The Total Tank Wipeout. The skin of the Boxfish produces a terrifyingly lethal neurotoxin. THE FATAL MISTAKE: If you keep this fish with aggressive bullies (Damsels, Tangs) or if it gets severely stressed, sick, or dies... it will panic and release a massive cloud of Ostracitoxin directly into the water. Within minutes, EVERY SINGLE FISH IN THE TANK (including the boxfish itself) WILL CHOKE TO DEATH AND DIE. Your entire tank will be 'nuked', requiring a 100% water change and heavy carbon filtration to make it safe again. They MUST only be kept with ultra-peaceful, slow fish.

The Clumsy Swimmer and Powerhead Death:

The Suction Trap. Because they are literally trapped inside a rigid bony box, they are the weakest, slowest swimmers in the ocean. They absolutely CANNOT survive in a high-flow Reef Tank. They will be blown away by the current, exhausted, and eventually sucked flat against the intake grate of a filter or wavemaker. When they get stuck to the filter, they panic and release the poison, killing everything. You MUST wrap all filters in soft foam pre-sponges to protect them.

The Color Fading and Massive Size:

The Brown Brick. You buy them at 1 inch. Within a few years, they balloon to a staggering 18 inches (45 cm). Worse, as they mature, they completely lose their beautiful, iconic bright yellow neon color. The adult Boxfish turns into a dull, ugly mustard-brown or faded blue giant brick. They demand massive 150+ gallon tanks.