A goldfish dropped somewhere?

Did you know that there's a goldfish tank on display inside the Sea Tokyo Sea Life Park?

We're not displaying them simply because they're beautiful. Goldfish have a deep historical connection to Edogawa Ward, where Tokyo Sea Life Park is located.

Since the Meiji era, Edogawa Ward has been rich in water resources, leading to the concentration of goldfish farms, and it eventually became one of the three major goldfish producing areas. Although urbanization has led to a decrease in the number of goldfish farmers, the area still has a deep connection with goldfish, as evidenced by the annual "Edogawa Ward Specialty Goldfish Festival," which features goldfish exhibitions and sales.

While cleaning the goldfish tanks before opening the park, I sometimes find small white fragments at the bottom of the tanks. They are only about 2-3 mm in size. They look like pieces of plastic, and at first I wondered, "What could that be?"

Actually, these were goldfish teeth.

Some people might be surprised and ask, "Is it okay if their teeth fall out?", but goldfish teeth are designed to grow back and be replaced many times throughout their lives.

Sharks are famous for shedding their teeth, but goldfish don't seem to have sharp teeth like sharks.

Goldfish have teeth called "pharyngeal teeth" that line the back of their throats. These pharyngeal teeth are not used to tear food apart, but rather to grind hard foods.

Fish of the Cyprinidae family, including goldfish, are known for their particularly well-developed pharyngeal teeth. By biting down on these teeth with a part called the "chewing plate," they can effectively crush their food. Goldfish have four teeth on each side, for a total of eight, making them truly versatile teeth that can grind up both animal and plant food.

Goldfish are a familiar creature, but once you understand how they work, you'll appreciate not only their beauty but also the wonder and depth of their nature as living things.

Summer festival season is just around the corner. When you're raising goldfish you got at a goldfish scooping game, or when you're looking at your goldfish tank, be sure to look for the little "dropped items" that have fallen to the bottom of the tank.

[Kotaro Sakamoto, Animal Care and Exhibition Staff, Tokyo Sea Life Park]