2026.02.20

Living creature information

[Limited Time Only] Baby Barrier reef chromis on Display

Baby Barrier reef chromis, a species of damselfish endemic to the Great Barrier Reef, the world's largest coral reef, are on display for a limited time at the aquarium keeper counter on the 4th floor of the entrance building. These babies were hatched in the tank after the Great Barrier Reef tank was renovated, with the eggs laid by the parent fish being collected by the aquarium keeper. Although still small, they have grown to the point where their distinctive features, such as their yellow heads and the black stripe running from their eyes to their dorsal fins, are clearly visible. You can also watch aquarium keeper explain the species and feed them daily from 1:10 PM to around 2:00 PM. Information about the breeding behavior of Barrier reef chromis and other damselfish species is also available on the blog "Behind the Scenes at Kaiyukan ." Period: February 20, 2026 - April 20, 2026 (tentative) Location: aquarium keeper Counter, 4th Floor, Kaiyukan Entrance Building *The exhibition may be suddenly canceled depending on the condition of the animals. Barrier reef chromis ( English name: Barrier reef chromis, scientific name: Chromis nitida) is a species endemic to the Great Barrier Reef. Among damselfish, which are generally territorial and aggressive, it has a relatively gentle temperament.

2025.11.19

Living creature information

The Tufted puffin , an endangered seabird that has been artificially raised by aquarium keeper , will be exhibited!

You can see it in the "Aleutian Islands" tank from Monday, December 1st. The "Aleutian Islands" tank , which has been undergoing renovations since April 9th, will reopen on Monday, December 1st, 2025. To coincide with this, a juvenile tufted Tufted puffin (one bird) will make its debut, having been hand-raised by aquarium keeper in the backyard. The Tufted puffin making its debut this time was born in the backyard on August 25th, 2025. From the moment it was born, aquarium keeper took on the role of parent, feeding it and weighing it. From October 20th, aquarium keeper began accompany- ing it in the pool to train it to swim at the same speed as an adult bird. While it now looks like a typical waterfowl, its beak is smaller and darker in color than an adult bird, giving it a youthful, innocent appearance. ▼Swimming training by the aquarium keeper[About the young Tufted puffin puffins] - Egg laying date: Friday, July 18, 2025 - Hatching date: Monday, August 25, 2025 - Gender: Unknown - Weight: 54g (immediately after hatching) → 610g (as of November 19, 2025) *Exhibition may be suspended without notice depending on the animal's condition. Comment from the Tufted puffin aquarium keeper: First of all, we hope they quickly get used to their new environment, the "Aleutian Islands" tank. We've also been training them to swim thoroughly in the back yard, but their swimming style is still clumsy and very adorable, so we hope many visitors will come and see their charms, which are only seen when they are young. [About the Tufted puffin] English name: Tufted Puffin Scientific name: Fratercula cirrhata This seabird is found widely in the subarctic zone of the North Pacific Ocean. Currently, breeding has only been confirmed in certain areas of Hokkaido, Japan, but numbers are small and it is classified as endangered (Category IA) on the Ministry of the Environment's Red List.

2025.10.07

Living creature information

Two baby King penguin born

~Watch the heartwarming raising of their young~ Two baby King penguin were born in the "Antarctica" tank on Tuesday, September 16th and Wednesday, September 24th, 2025. Both babies have been raised under the stomachs of their parents since birth, making it difficult to see them, but we are pleased to announce that the first baby has started to occasionally pop its head out from under its parents' feet, providing more opportunities to see the raising of the young, such as being fed by mouth. Both babies are thriving, and aquarium keeper are monitoring their growth by weighing them every morning. First baby (photographed on October 6th) [About the baby King penguin] [First baby] Hatching date: Tuesday, September 16th, 2025 Gender: Unknown Weight: 244g (immediately after hatching) → Approximately 1,380g (as of October 7th) [Second baby] Hatching date: Wednesday, September 24th, 2025 Gender: Unknown Weight: 192g (immediately after hatching) → Approximately 350g (as of October 7th) *Depending on the condition of the babies, the exhibit may be canceled without notice.

2025.09.18

Living creature information

A baby tufted Tufted puffin , an endangered seabird, is born. A special experience event will also be held where you can see the aquarium keeper' perspective.

2025.08.04

Living creature information

[Exhibition closed] After a three-year hiatus, the large Ariake Bizen Kurage (Japanese Name) is now on display!

The Ariake Bizen Kurage (Japanese Name), a large jellyfish native to the Ariake Sea, has been exhibited for a limited period of approximately one month. This marks the first time a large specimen of this species has been exhibited at Kaiyukan in three years, since 2022. Kaiyukan has been conducting research on the Ariake Bizen Kurage (Japanese Name) in the Ariake Sea since 2001, and in 2002 successfully transported and reared a large specimen for the first time. This year, we once again collected a Risen jellyfish for research and display, coinciding with the start of jellyfish fishing in the Ariake Sea. Through this exhibit, Kaiyukan hopes to provide an opportunity for visitors to develop an interest in living creatures and the natural environment. Exhibit location: "Jellyfish"*Exhibit has closed. Exhibits: 3 (umbrella diameter approximately 50 cm) *Exhibit period and number of specimens may change without notice depending on the condition of the creatures. About the Ariake Bizen Kurage (Japanese Name) Scientific name: Rhopilema esculentum It lives in coastal waters of tropical, subtropical, and warm temperate zones, and is found in the Seto Inland Sea and Ariake Sea in the waters around Japan. It is a large jellyfish that grows to an umbrella diameter of 60 cm and weighs about 20 kg, and is known in English as "edible jellyfish" because it is edible. It is caught in gillnet fishing off the coast of the Ariake Sea from July to October. In recent years, the name was changed from a type of Rhopilema esculentum to "Ariake Bizen Kurage (Japanese Name)" to avoid confusion with similar species.

2025.06.18

Living creature information

[They are growing rapidly] Three Southern rockhopper penguin chicks born

You can see the raising of the chicks in the exhibition tank . On May 29th (Thursday), June 7th (Saturday), and June 9th (Monday), 2025, three Southern rockhopper penguin chicks were born in the "Falkland Islands(Malvinas)" tank . The Southern rockhopper penguin kept in the "Falkland Islands(Malvinas)" tank entered their breeding season in late April, and three pairs were formed, one chick each, for a total of three chicks. Currently, the parents are raising the chicks in their own nests, and you can see them occasionally feeding the chicks by mouth. The chicks born earlier are also growing well, with the chick born on May 29th weighing over 1kg and the chick born on June 7th weighing over 500g. aquarium keeper are watching over the raising of the chicks, checking their health by weighing and observing them every morning. A parent and child of the Southern rockhopper penguin(photographed on June 11th) [About the Southern rockhopper penguin chicks] [1st chick] Hatching date: Thursday, May 29th, 2025 Gender: Unknown Weight: 75.3g (immediately after hatching) 1.1kg (as of June 18th) [2nd chick] Hatching date: Saturday, June 7th, 2025 Gender: Unknown Weight: 64.1g (immediately after hatching) 556.2g (as of June 18th) [3rd chick] Hatching date: Monday, June 9th, 2025 Gender: Unknown Weight: 49.7g (immediately after hatching) 235.8g (as of June 18th)

2025.06.13

Living creature information

California sea lion baby born

On Thursday, June 12, 2025, a baby California sea lion was born in the "Monterey Bay" tank . This is the 19th birth of a California sea lion at Kaiyukan . From Wednesday, June 11, 2025, the female "Asuka (15 years old)" living in the "Monterey Bay" tank was found to be showing signs of giving birth, and the aquarium keeper were observing her 24 hours a day. At 8:00 a.m. on Thursday, June 12, the baby was safely born. Both mother and child are healthy, and you can see the nursing and other child-rearing activities in the "Monterey Bay" tank. We would like to watch the baby grow up so that it will grow up healthily. Please note that the baby may be moved to the back yard depending on the situation, and you may not be able to see it. Thank you for your understanding. Appearance of parent and child (photographed on 6/12) About the newborn baby (as of June 12, 2025) (photographed on 6/12) ・Date of birth: Thursday, June 12, 2020 ・Display tank : "Monterey Bay" tank on the 7th floor of Kaiyukan・Body length: 60 cm (estimated) ・Weight: 9.4 kg (actual measurement) ・Gender: Male ・Parents: Mother Asuka (15 years old), father unknown About California sea lion English name: California sea lion Scientific name: Zalophus californianus They live only on the eastern coast of the North Pacific Ocean Ocean. When fully grown, males reach a body length of about 200 cm and a weight of about 300 kg, while females reach a body length of about 170 cm and a weight of about 100 kg. Males are dark brown all over, while females are a slightly lighter dark brown. Their limbs are well developed, which is useful not only for swimming underwater but also for walking on land. They are polygamous, with one male leading about 30 females and their children in groups called "harems." The gestation period is about one year. Usually, one child is born at a time, and the baby continues to be nursed for about one year after birth. Comments from the California sea lion aquarium keeper California sea lion breed seasonally, and the fertilization period is limited to a very short period of the year. It is very difficult to determine the date of birth by observing the behavior seen during the breeding season, such as mating. This time, the aquarium keeper and veterinarians worked closely together to determine the date of birth by regular ultrasound examinations and weight measurements, so that the mother could give birth with even more peace of mind. Because of this, on the day of birth, many aquarium keeper watched over the birth, and all the aquarium keeper were filled with joy. All the aquarium keeper in charge will continue to work together to provide care so that Asuka can raise her children with peace of mind and that the baby will grow up healthy and strong.

2025.05.29

Living creature information

A first for the Kaiyukan! A large shark called the Sand tiger Shark is now on display

Kaiyukan has begun exhibiting the "Sand tiger Shark." This is the first time this species has been exhibited at Kaiyukan. Left: Male Right: Sand tiger Shark are a large shark species that can grow to over 3m in length. Contrary to their fearsome appearance with their large, bared teeth, they have a docile personality and live in coral reefs, shallow offshore waters, and underwater caves. Two sharks, a 2.7m female and a 2.5m male, were brought to the "Pacific Ocean" tank from the Tokai University Marine Science Museum. They have now gotten used to their new environment, swimming leisurely in the tank and eating food provided by the aquarium keeper during " Feeding Time " twice a day. Exhibit location: "Pacific Ocean" tank . Individuals exhibited: Female: 2.7m in length, delivered on Monday, May 12, 2025. Male: 2.5m in length, delivered on Thursday, May 15, 2025. About the Sand Tiger Shark: English name: Sand tiger shark. Scientific name: Carcharias taurus. A large shark with a total length of over 3m. It inhabits warm seas such as coral reefs and shallow offshore waters, and is currently said to only inhabit the Ogasawara Islands (Mukojima Islands, Chichijima Islands, and Hahajima Islands) in Japan. It hides in underwater caves during the day and is nocturnal, active at night, feeding mainly on other fish. Contrary to its fearsome appearance, it has a docile personality. It is viviparous, has two uteruses, and produces up to two young with a total length of about 1m per breeding. The fetuses are known to grow by eating other eggs and siblings in the uterus.

2025.04.24

Living creature information

*Exhibition has ended. [First exhibit at Kaiyukan] We are exhibiting the "megalopa larvae" of the Japanese giant spider crab.

*Exhibition has ended. Starting from April 23rd, Japanese giant spider crab larvae hatched in the "Japan Deep" tank will be on display for a limited time at the aquarium keeper counter on the 4th floor of the entrance building. On Friday, March 7th, 2025, a aquarium keeper discovered a baby Japanese giant spider crab being born in the "Japan Deep" tank and raised it carefully in the back yard. Immediately after birth, Japanese giant spider crab babies are called "zoea larvae" and have a different appearance from adults. They grow into "megalopa larvae" by repeatedly molting, and then into "juvenile crabs" that look the same as adults. They have now grown into megalopa larvae (about 3 mm), so please take a look at the precious appearance of the world's largest crab, the Japanese giant spider crab, which can only be seen now. The growth of Japanese giant spider crab larvae is also introduced in the blog "Behind the Scenery of Kaiyukan". Period: 2025/04/23~ Kaiyukan Kaiyukan Entrance Building 4F aquarium keeper Counter Species: Japanese giant spider crab megalopa larvae (approximately 3mm in size) Approximately 5 pieces *Exhibition may be canceled suddenly depending on the condition of the creatures. Japanese giant spider crab English name: Japanese giant spider crab Scientific name: Macrocheira kaempferi The world's largest crab, with males reaching over 3m in length when their tines are spread. It is also the world's largest species of arthropod, a larger taxonomic group, and is found mainly in the waters off the coast of Japan, but has also been caught in Taiwan and other places. They usually live in deep sea areas, and are known to move to shallow waters in the spring to spawn.

2025.03.28

Living creature information

[Notice] Renovation work on the "Aleutian Islands" tank [From April 9th]

Please note that the "Aleutian Islands" tank will be closed to the public from April 9, 2025 due to preparations to improve the breeding environment. Construction is scheduled to be completed after autumn 2025. We plan to report on the life of the Tufted puffin puffins in the back yard on the "Behind the Scenes at Kaiyukan " blog on the Kaiyukan website.