The main distribution area for the surgeonfish is southern Japan, but there have also been reports from Taiwan and Hong Kong. They can be found in shallow rocky areas, and while juveniles are solitary, adults form schools and can grow up to 50 centimeters in length.

Adult fish are easily recognizable by the four to five black spots lined up at the base of their tails. Each of the spots at the rear has a single spine (a plate-like protrusion), with three to four on each side. These spines are sharp and are used as weapons in fights with other fish or to defend themselves from enemies. Be careful when trying to grab them carelessly after catching them, as you may suffer a serious injury from these spines. The cut is said to be as sharp as being cut by a blade, and is accompanied by intense pain.

These thorns are said to be poisonous, but the details are not well understood.

Recent research has also revealed that the hard spines on the dorsal, anal, and possibly pelvic fins are also venomous. While this venom doesn't seem to be particularly potent, it should still be effective in protecting the fish. I myself have experienced something more than just the pain of a spine when I was pricked by a juvenile surgeonfish.

The body color of the surgeonfish is usually uniformly gray, but occasionally, for a few seconds, it can display artistic designs on its body.

If you observe the surgeonfish in the exhibit tank in the "Tokyo Sea" Tokyo Sea Life Park, you'll notice that the markings on their bodies appear to be a form of greeting (signal) to other members of their group, although the exact meaning and usage are unknown. If you have the opportunity, why not take a look?

Photo above: Sharp, knife-like spines at the base of the tail
Photo below: Artistic designs occasionally appearing on the body

[Tokyo Sea Life Park]

(October 22, 2010)