Common name: Upside-down Jellyfish

General Information

The Upside-down Jellyfish, scientifically known as Cassiopea andromeda, is a fascinating species that often intrigues aquarium enthusiasts with its unique lifestyle. Unlike most jellyfish that float through the water, this species spends much of its time resting upside down on the substrate, showcasing its bell with its tentacles facing upwards. This distinctive behavior is due to its symbiotic relationship with photosynthetic algae, which live in its tissues and require sunlight.

This jellyfish is a popular addition to marine aquariums due to its unusual appearance and relatively peaceful nature. It plays a role in educational exhibits, teaching about symbiosis and marine life. However, it’s important to note that the Upside-down Jellyfish can release a mild sting, which can cause irritation to sensitive individuals.

Care

Cassiopea andromeda requires a well-maintained aquarium with stable water conditions. It thrives in shallow tanks where it can receive ample light to support its symbiotic algae. A sandy substrate is ideal, allowing the jellyfish to rest comfortably. While it can adapt to various tank setups, it’s crucial to avoid strong currents that could disrupt its preferred resting position.

Diet and Feeding

This jellyfish primarily relies on the photosynthetic algae within its tissues for nutrition. However, it also benefits from supplemental feeding with small planktonic foods like brine shrimp or rotifers. Regular feeding ensures that the jellyfish receives all necessary nutrients, especially in environments with less than optimal lighting.

Behavior and Compatibility

The Upside-down Jellyfish is generally peaceful and can be housed with other non-aggressive marine species. It does not actively hunt or pose a threat to other tank inhabitants, making it a suitable candidate for community tanks. However, care should be taken to avoid housing it with species that may disturb its resting behavior or outcompete it for food.

Symbiosis

Cassiopea andromeda has a remarkable symbiotic relationship with zooxanthellae, a type of photosynthetic algae. This relationship allows the jellyfish to derive energy from sunlight, similar to corals. This mutualistic partnership is beneficial in nutrient-poor environments, allowing the jellyfish to thrive in diverse conditions.

Health and Common Issues

In captivity, the Upside-down Jellyfish can live for several years if provided with proper care. Maintaining clean water, providing adequate lighting, and ensuring a balanced diet are essential for its health. Watch for signs of stress or poor health, such as discoloration or unusual floating behavior, which may indicate water quality issues or inadequate lighting.

Habitat

Cassiopea andromeda is naturally found in shallow coastal lagoons and mangrove swamps in the Indo-Pacific region, including areas such as the Red Sea, East Africa, and the western Pacific Ocean. It prefers warm, sunlit waters where it can easily access sunlight for its symbiotic algae.