Yokohama Hakkeijima Sea Paradise's aquarium, Aqua Museum, will launch a new exhibit on June 29, 2026, allowing visitors to observe the growth process of the Japanese lumpsucker (Eumicrotremus awae) born at the facility.

This exhibit enables guests to simultaneously view three different developmental stages of lumpsuckers born at the aquarium: just after hatching, several months after birth, and fully mature adults.

Lumpsuckers undergo dramatic physical changes as they grow. In their early stage, measuring just a few millimeters in length, they display a charming appearance with a ring-shaped white line on their heads—commonly known as the "angel's ring." As they mature, they gradually transform into the form of adult lumpsuckers.

Moving forward, the facility will continue to provide opportunities for visitors to learn about the charm and ecology of lumpsuckers and other marine life. As part of the aquarium’s core mission of species conservation, it will also continue its planned breeding programs.

New Lumpsucker Exhibit

Located in LABO 3, "Animals Evolved in the Sea," on the 1st floor of Aqua Museum, this exhibit allows simultaneous observation of three distinct growth stages of lumpsuckers born at the facility: just after hatching, several months after birth, and adult.

Lumpsuckers undergo significant morphological changes as they grow. In their juvenile stage, they possess the distinctive "angel's ring"—a white circular marking on the head—which fades as they mature into adults.

About the Japanese Lumpsucker

The Japanese lumpsucker (Eumicrotremus awae) is a fish belonging to the family Cyclopteridae, order Scorpaeniformes, found in shallow rocky reefs and seaweed beds along Japan’s coastlines. It is characterized by its round, endearing body and a powerful suction disc formed from modified pelvic fins, allowing it to cling tightly to rocks and seaweed. Its body color varies—red, green, or brown—depending on its habitat. During winter, it moves into shallower waters to spawn, and its large eyes and cute appearance make it a favorite among divers and marine enthusiasts.

Lumpsucker Breeding Program

Since 2026, the facility has been actively engaged in breeding Japanese lumpsuckers as part of its commitment to species conservation, one of the key roles of modern aquariums.

Lumpsuckers have a unique reproductive cycle: females lay eggs, which males then guard. The breeding season begins in winter as seawater temperatures drop.

In the wild, males establish territories inside barnacles or coiled shells, attracting females for mating. Once paired successfully, the female deposits her eggs inside the cavity, and the male guards them until they hatch. In captivity, PVC pipes are used as artificial nesting sites in place of natural shells, providing a safe and controlled breeding environment.

After spawning, the male diligently cares for the eggs, which hatch after several weeks to about one month into larvae approximately 3 mm in length. These larvae exhibit the "angel's ring" on their heads—a white circular pattern that typically disappears after about two weeks. As they grow, they gradually take on the appearance of adult lumpsuckers.

Exhibit Details

- Location: LABO 3, "Animals Evolved in the Sea," 1st Floor, Aqua Museum

Lumpsucker Species Information

- Classification: Order Scorpaeniformes, Family Cyclopteridae - English Name: Japanese lumpsucker - Scientific Name: Eumicrotremus awae

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  • Source: PR TIMES
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